There is no register of the web, so every measurement substitutes a list for the population it wants to talk about. This page is about which list: what each ranking actually measures, what it is biased towards, and which ones the field still uses. Sampling is about how you draw from a list you have already chosen — top-n versus stratified, sample size, unit, versioning. Read them together. A reader can pick CrUX, know its biases, and still produce an unreproducible top-1,000 crawl with no list id.

This page overlaps with Website classification only in that popularity is one label people attach to sites. Classification is about topic, industry and company data. Rankings are the sampling frame.

The single most useful thing to internalise is that “a top-sites list” is not one instrument. The vendors measure different things, they disagree on the head, and a Tranco row is a mixture of those instruments rather than a ground truth:

The short version, from 1,153 papers in our corpus of seven security and privacy venues that drew a population of websites, domains or web pages (see Use in Publications):

If you read three papers before starting: [2Scheitle, Quirin; Hohlfeld, Oliver; Gamba, Julien; Jelten, Jonas; Zimmermann, Torsten; Strowes, Stephen D.; Vallina-Rodriguez, Narseo (2018): "A Long Way to the Top: Significance, Structure, and Stability of Internet Top Lists", in: Proceedings of the Internet Measurement Conference 2018, pp. 478–493. Association for Computing Machinery, New York, NY, USA. (DOI) (Link)] (IMC 2018) on overlap, churn and head-vs-zone bias; [3Le Pochat, Victor; Van Goethem, Tom; Tajalizadehkhoob, Samaneh; Korczy´nski, Maciej; Joosen, Wouter (2019): "Tranco: A Research-Oriented Top Sites Ranking Hardened Against Manipulation", in: Proceedings of the 26th Annual Network and Distributed System Security Symposium. (DOI)] (NDSS 2019) on manipulation and why Tranco exists; [1Ruth, Kimberly; Kumar, Deepak; Wang, Brandon; Valenta, Luke; Durumeric, Zakir (2022): "Toppling Top Lists: Evaluating the Accuracy of Popular Website Lists", in: Proceedings of the 22nd ACM Internet Measurement Conference, pp. 374–387. Association for Computing Machinery, New York, NY, USA. (DOI) (Link)] (IMC 2022) on which list matched HTTP logs. [4Galloway, Tillson; Karakolios, Kleanthis; Ma, Zane; Perdisci, Roberto; Keromytis, Angelos D.; Antonakakis, Manos (2024): "Practical Attacks Against DNS Reputation Systems", in: Proceedings of the IEEE Symposium on Security and Privacy. (DOI)] (IEEE S&P 2024) is the current attack paper, and it is about Radar and Tranco-via-Radar, not about CrUX.

Each list ranks an observable that people then treat as popularity. The observable is the whole design:

• Page loads (CrUX): user-initiated navigations from eligible Chrome installs. Closest to “sites people visit”.
• DNS queries (Umbrella, Radar, Farsight, SecRank): names resolvers looked up. Includes software updates, telemetry, CDNs and names no human opened.
• Backlinks (Majestic): the link graph. Independent of visits; cheap to manipulate relative to a panel [3Le Pochat, Victor; Van Goethem, Tom; Tajalizadehkhoob, Samaneh; Korczy´nski, Maciej; Joosen, Wouter (2019): "Tranco: A Research-Oriented Top Sites Ranking Hardened Against Manipulation", in: Proceedings of the 26th Annual Network and Distributed System Security Symposium. (DOI)].
• An aggregate (Tranco): Dowdall over a month of several of the above. More stable than a single daily source; not a fourth kind of popularity, and not CrUX.

Tranco's daily list of 2026-08-26 (id 46W9X) mixes CrUX with three DNS rankings and Majestic. Treating that id as “the CrUX top 1M” is a methods error; treating it as “websites” is the same error one layer down. The script below looks the same names up on that Tranco list, Umbrella and Majestic (fetched 2026-08-27T14:26:07Z):

Umbrella still publishes a separate TLD file (top-1m-TLD.csv.zip, 10,905 rows on 2026-08-27: com = 1, net = 2, org = 6). Bare TLDs are not in the 2026-08-27 top-1m.csv — an earlier version of this page described the popularity list as beginning 1,com / 2,net. That is the TLD file, not the list you crawl.

Looks the same names up on the three lists you can fetch without an account. Stdlib only. Rerun it on the day you freeze a sample; the table above is the latest Tranco daily list as of the fetch (dated 2026-08-26, fetched 2026-08-27T14:26:07Z), plus that day's Umbrella zip and Majestic CSV.

compare_ranks.py

#!/usr/bin/env python3
"""Look the same names up on today's Tranco daily list, Cisco Umbrella, and
Majestic Million, and print the ranks side by side.
 
The point is not the ranks. It is that they disagree, and that Umbrella ranks
TLDs and infrastructure hostnames a page-load list does not contain.
 
    python3 compare_ranks.py
    python3 compare_ranks.py --wiki
 
Stdlib only. Caches the bulk CSVs under /tmp/measuretheweb-compare-ranks.
Tranco is a ranks API (1 query/second). Dated in the output; rerun before you
cite the table.
"""
from __future__ import annotations
 
import argparse
import csv
import hashlib
import io
import json
import sys
import time
import urllib.request
import zipfile
from datetime import datetime, timezone
from pathlib import Path
 
UA = "measuretheweb-compare-ranks/1.0"
CACHE = Path("/tmp/measuretheweb-compare-ranks")
CACHE.mkdir(parents=True, exist_ok=True)
 
TRANCO_RANKS = "https://tranco-list.eu/api/ranks/domain/{domain}"
TRANCO_LATEST = "https://tranco-list.eu/api/lists/date/latest"
UMBRELLA_ZIP = "https://s3-us-west-1.amazonaws.com/umbrella-static/top-1m.csv.zip"
UMBRELLA_TLD_ZIP = "https://s3-us-west-1.amazonaws.com/umbrella-static/top-1m-TLD.csv.zip"
MAJESTIC_CSV = "https://downloads.majestic.com/majestic_million.csv"
 
# Names chosen to hit the disagreements the rest of the page argues: a page
# people visit, a news site, a Chinese head, DNS/update infrastructure, and a
# hostname vs its registrable domain. Bare TLDs are a separate Umbrella file
# (top-1m-TLD.csv.zip); they are not in the top-1m this script loads.
NAMES = [
    "google.com",
    "facebook.com",
    "wikipedia.org",
    "baidu.com",
    "nytimes.com",
    "microsoft.com",
    "gstatic.com",
    "windowsupdate.com",
    "windowsupdate.microsoft.com",
    "googleusercontent.com",
]
 
 
def fetch(url: str) -> bytes:
    req = urllib.request.Request(url, headers={"User-Agent": UA})
    with urllib.request.urlopen(req, timeout=180) as resp:
        return resp.read()
 
 
def cached(url: str, name: str) -> Path:
    path = CACHE / name
    if path.exists() and path.stat().st_size > 0:
        return path
    path.write_bytes(fetch(url))
    return path
 
 
def load_rank_csv(path: Path, domain_col: int, rank_col: int, skip_header: bool) -> dict[str, int]:
    raw = path.read_bytes()
    if raw[:2] == b"PK":
        with zipfile.ZipFile(io.BytesIO(raw)) as zf:
            text = zf.read(zf.namelist()[0]).decode()
    else:
        text = raw.decode(errors="replace")
    out: dict[str, int] = {}
    reader = csv.reader(io.StringIO(text))
    if skip_header:
        next(reader)
    for row in reader:
        if len(row) <= max(domain_col, rank_col):
            raise RuntimeError(f"{path}: short row {row!r}")
        domain = row[domain_col].strip().lower()
        rank = int(row[rank_col])
        if domain in out:
            continue
        out[domain] = rank
    if len(out) < 1000:
        raise RuntimeError(f"{path}: only {len(out)} rows — file is not a top list")
    return out
 
 
def tranco_today(domain: str) -> int | None:
    raw = fetch(TRANCO_RANKS.format(domain=domain))
    body = json.loads(raw.decode())
    ranks = body["ranks"]
    if len(ranks) == 0:
        return None
    rank = ranks[0]["rank"]
    if rank is None:
        return None
    return int(rank)
 
 
def fmt(rank: int | None) -> str:
    if rank is None:
        return "absent"
    return f"{rank:,}"
 
 
def main() -> int:
    ap = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
    ap.add_argument("--wiki", action="store_true", help="DokuWiki table instead of TSV")
    args = ap.parse_args()
 
    meta = json.loads(fetch(TRANCO_LATEST).decode())
    list_id = meta["list_id"]
    cfg = meta["configuration"]
    fetched_at = datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ")
 
    umbrella_path = cached(UMBRELLA_ZIP, "umbrella_top1m.csv.zip")
    majestic_path = cached(MAJESTIC_CSV, "majestic_million.csv")
    umbrella = load_rank_csv(umbrella_path, domain_col=1, rank_col=0, skip_header=False)
    majestic = load_rank_csv(majestic_path, domain_col=2, rank_col=0, skip_header=True)
 
    rows: list[tuple[str, int | None, int | None, int | None]] = []
    for i, name in enumerate(NAMES):
        if i:
            time.sleep(1.05)
        t = tranco_today(name)
        u = umbrella[name] if name in umbrella else None
        m = majestic[name] if name in majestic else None
        rows.append((name, t, u, m))
 
    if rows[0][0] != "google.com" or rows[0][1] is None:
        raise RuntimeError("google.com missing from Tranco — the ranks API changed")
    if "gstatic.com" not in umbrella:
        raise RuntimeError("gstatic.com missing from Umbrella — the zip changed shape")
    tld_path = cached(UMBRELLA_TLD_ZIP, "umbrella_top1m_tld.csv.zip")
    tld = load_rank_csv(tld_path, domain_col=1, rank_col=0, skip_header=False)
    if "com" not in tld:
        raise RuntimeError("TLD 'com' missing from Umbrella top-1m-TLD.csv.zip")
 
    print(f"fetched_at {fetched_at}")
    print(f"tranco {list_id} providers {','.join(cfg['providers'])} {cfg['combinationMethod']}")
    print(f"umbrella sha256 {hashlib.sha256(umbrella_path.read_bytes()).hexdigest()[:12]} n={len(umbrella)}")
    print(f"majestic sha256 {hashlib.sha256(majestic_path.read_bytes()).hexdigest()[:12]} n={len(majestic)}")
    print(
        "umbrella TLD file: "
        f"com={tld['com']} net={tld['net']} org={tld['org']} n={len(tld)}"
    )
    print()
    if args.wiki:
        print("^ Name ^ Tranco (PLD, " + list_id + ") ^ Cisco Umbrella (hostname) ^ Majestic Million (backlinks) ^")
        for name, t, u, m in rows:
            print(f"| ''{name}'' | {fmt(t)} | {fmt(u)} | {fmt(m)} |")
    else:
        print("name\ttranco\tumbrella\tmajestic")
        for name, t, u, m in rows:
            print(f"{name}\t{fmt(t)}\t{fmt(u)}\t{fmt(m)}")
    return 0
 
 
if __name__ == "__main__":
    sys.exit(main())

To pin a Tranco id rather than compare ranks, use python3 pin_tranco.py on Tranco.

Checked against each vendor's own documentation and APIs on 2026-08-27. Dated deliberately.

CrUX publishes rank-magnitude buckets (1k, 5k, 10k, …, 5M) of popular origins based on user-initiated page loads from eligible Chrome installs — usage-statistic reporting, history sync without a passphrase, and a supported platform (not Chrome on iOS).¹⁾ There is no rank 5,000. Country- and device-specific slices exist; they measure Chrome page loads in that country, not “sites for that audience” — see Website classification. API detail: CrUX. Galloway et al. did not evaluate it [4Galloway, Tillson; Karakolios, Kleanthis; Ma, Zane; Perdisci, Roberto; Keromytis, Angelos D.; Antonakakis, Manos (2024): "Practical Attacks Against DNS Reputation Systems", in: Proceedings of the IEEE Symposium on Security and Privacy. (DOI)].

Tranco is a research-oriented generator with permanent list ids, introduced in NDSS 2019 [3Le Pochat, Victor; Van Goethem, Tom; Tajalizadehkhoob, Samaneh; Korczy´nski, Maciej; Joosen, Wouter (2019): "Tranco: A Research-Oriented Top Sites Ranking Hardened Against Manipulation", in: Proceedings of the 26th Annual Network and Distributed System Security Symposium. (DOI)] combining Alexa, Umbrella, Majestic and Quantcast. Its inputs have changed three times (Quantcast dropped after 2020-04-01, Farsight joined 2022-05-01, Alexa replaced by CrUX and Radar on 2023-08-01). The daily list of 2026-08-26 (id 46W9X) is CrUX, Farsight, Majestic, Radar and Umbrella, Dowdall over 30 days, filterPLD: on, prefix 1,000,000.²⁾ A 2019 id and a 2026 id are different instruments. Radar's CC BY-NC 4.0 rides along on the default list. API, Farsight trap, pin_tranco.py: Tranco.

Cloudflare Radar Domain Rankings ranks pay-level domains from DNS queries to 1.1.1.1, not from HTTP hits on Cloudflare-operated websites. Ordered top 100 (daily, global and per country) plus unordered buckets up to 1M (weekly). Details: Cloudflare Radar. Manipulable with a cheap VPN [4Galloway, Tillson; Karakolios, Kleanthis; Ma, Zane; Perdisci, Roberto; Keromytis, Angelos D.; Antonakakis, Manos (2024): "Practical Attacks Against DNS Reputation Systems", in: Proceedings of the IEEE Symposium on Security and Privacy. (DOI)].

Cisco Umbrella ranks names by DNS query traffic to OpenDNS resolvers. The daily top-1m zip was still published on 2026-08-27. Today's file is hostnames: 1,google.com / 2,gstatic.com / 3,www.google.com. The vendor page still says the list “includes root domains, subdomains in addition to TLDs”; the TLD ranking is a different zip (above). Typos and infrastructure hostnames survive. Still a Tranco default input.

Majestic ranks domains by backlinks. The Million page still advertised free search and download on 2026-08-27 (downloads.majestic.com/majestic_million.csv). CC BY 3.0, per Tranco. Does not measure visits. Link-graph rankings are cheap to manipulate relative to a toolbar or panel list [3Le Pochat, Victor; Van Goethem, Tom; Tajalizadehkhoob, Samaneh; Korczy´nski, Maciej; Joosen, Wouter (2019): "Tranco: A Research-Oriented Top Sites Ranking Hardened Against Manipulation", in: Proceedings of the 26th Annual Network and Distributed System Security Symposium. (DOI)]. That paper did not evaluate CrUX.

A 1-million pay-level-domain ranking built from cache-misses in Farsight's DNSDB — “above-resolver” DNS that organisations share, so a name that stays in a recursive cache is invisible. Tranco has used it as a default input since 1 May 2022, the same day Alexa.com was retired.³⁾ It is not a public CSV. You get it only as part of Tranco's daily list: the custom-list API's providers enum is crux / majestic / radar / umbrella / alexa / quantcast — Farsight, which is in the daily list, is not in that enum. See Tranco. Zero papers in this corpus name the Farsight ranking as a sourceList. The 13 papers that name Farsight or DNSDB used the passive-DNS dataset, which is a different instrument.

• Alexa: Discontinued — alexa.com was retired on 1 May 2022 and the Alexa Top Sites and Web Information Service APIs on 15 December 2022.⁴⁾ Rankings came from a browser toolbar / panel [2Scheitle, Quirin; Hohlfeld, Oliver; Gamba, Julien; Jelten, Jonas; Zimmermann, Torsten; Strowes, Stephen D.; Vallina-Rodriguez, Narseo (2018): "A Long Way to the Top: Significance, Structure, and Stability of Internet Top Lists", in: Proceedings of the Internet Measurement Conference 2018, pp. 478–493. Association for Computing Machinery, New York, NY, USA. (DOI) (Link)]. Do not start a new crawl from an Alexa snapshot unless the study is a reproduction of a pre-2022 paper, in which case name the snapshot.
• Quantcast: Was a Tranco default input until 1 April 2020. The Measure product still exists as publisher analytics (quantcast.com/measure/ redirects to /publisher/measure); it is not a public top-sites ranking you can pin. Named by 8 papers, none in 2025–2026.
• SimilarWeb: Commercial panel and crawl estimates; paywalled (some research exceptions exist). See SimilarWeb. Named by 12 of 1,153 web-sampling papers.
• SecRank: Voting-based ranking from Chinese DNS, introduced in USENIX Security 2022 [5Xie, Qinge; Tang, Shujun; Zheng, Xiaofeng; Lin, Qingran; Liu, Baojun; Duan, Haixin; Li, Frank (2022): "Building an Open, Robust, and Stable Voting-Based Domain Top List", in: 31st USENIX Security Symposium (USENIX Security 22), pp. 625-642.]. Site live on 2026-08-27. Named by 4 papers. Use it when the audience is Chinese resolver traffic; it is not a drop-in Alexa replacement for a global crawl.

Ruth et al. compared public lists to Cloudflare HTTP logs in February 2022 [1Ruth, Kimberly; Kumar, Deepak; Wang, Brandon; Valenta, Luke; Durumeric, Zakir (2022): "Toppling Top Lists: Evaluating the Accuracy of Popular Website Lists", in: Proceedings of the 22nd ACM Internet Measurement Conference, pp. 374–387. Association for Computing Machinery, New York, NY, USA. (DOI) (Link)]:

of the 1,790 domains we measure in the Alexa top 10K, 70% of them are ranked by Cloudflare in a lower rank-magnitude bucket, and 27.2% of them are ranked by Cloudflare in a bucket two or more orders of magnitude less popular.

On the Alexa top 1K the same paper reports 87.1% overranked (average of 210 sites) and 56.7% by two or more orders. CrUX is the exception they found: 47.1% of 1,410 CrUX top-10K domains overranked against Cloudflare, and only 1% by two or more orders. “Inaccurate” is not a small permutation of the head; it is a different web. They did not evaluate the five-provider Tranco list current in 2026.

Scheitle et al. measured agreement between the lists themselves [2Scheitle, Quirin; Hohlfeld, Oliver; Gamba, Julien; Jelten, Jonas; Zimmermann, Torsten; Strowes, Stephen D.; Vallina-Rodriguez, Narseo (2018): "A Long Way to the Top: Significance, Structure, and Stability of Internet Top Lists", in: Proceedings of the Internet Measurement Conference 2018, pp. 478–493. Association for Computing Machinery, New York, NY, USA. (DOI) (Link)]: for the Top 1M, Alexa and Majestic shared 285k domains on average in their 2017–2018 joint window — well under a third. Daily churn reached 50% of domains on some lists. An unused test domain reached rank 22k on Umbrella.

Scheitle et al. compared list domains against the general com/net/org population [2Scheitle, Quirin; Hohlfeld, Oliver; Gamba, Julien; Jelten, Jonas; Zimmermann, Torsten; Strowes, Stephen D.; Vallina-Rodriguez, Narseo (2018): "A Long Way to the Top: Significance, Structure, and Stability of Internet Top Lists", in: Proceedings of the Internet Measurement Conference 2018, pp. 478–493. Association for Computing Machinery, New York, NY, USA. (DOI) (Link)]:

the HTTP/2 adoption of all com/net/org domains is 7.84% on average and thus significantly lower than for domains listed in Top 1M lists, (up to 26.6% for Alexa)

Top 1k lists showed adoption around 35% or more. The same paper's IPv6 and CDN gaps went the same way. On that indicator the head was a technological outlier; it is not a theorem that every later adoption measure will. How you draw from the head is Sampling.

DNS-based lists — Umbrella, Farsight, SecRank, and parts of Radar and Tranco — count resolver observations. That over-represents names that devices look up without a user opening a page. The table above is the current evidence: gstatic.com and windowsupdate.com sit in Tranco's head; windowsupdate.microsoft.com is an Umbrella hostname that a PLD list drops. An earlier draft of this page used ec2.internal as the running example; it is not in the 2026-08-27 Umbrella top-1m.

Galloway et al. generated names, queried them through a $10/month VPN, and “consistently achieved a ranking in the top 100,000” on Radar; Tranco then placed the same names at rank 1 million within 10 days and inside 500k within 14 days [4Galloway, Tillson; Karakolios, Kleanthis; Ma, Zane; Perdisci, Roberto; Keromytis, Angelos D.; Antonakakis, Manos (2024): "Practical Attacks Against DNS Reputation Systems", in: Proceedings of the IEEE Symposium on Security and Privacy. (DOI)]. They also sat consistently under rank 250,000 on Umbrella. On the Radar API as of 2026-08-27 that top 100,000 is an unordered bucket, not a total order — see Cloudflare Radar. That is a finding about Radar (and Tranco via that input), not about every DNS ranking, and not about CrUX.

Alexa, when it was live, ranked from a toolbar panel. Two problems, both measured:

• Manipulations: ranks could be altered with as little as a single HTTP request [3Le Pochat, Victor; Van Goethem, Tom; Tajalizadehkhoob, Samaneh; Korczy´nski, Maciej; Joosen, Wouter (2019): "Tranco: A Research-Oriented Top Sites Ranking Hardened Against Manipulation", in: Proceedings of the 26th Annual Network and Distributed System Security Symposium. (DOI)]. There was a real-world incentive to do this.
• Stability: a small panel, a large web, and a daily publish produced high churn.

Tranco was designed to reduce both by aggregating sources over 30 days. CrUX publishes buckets rather than a total order, so a name that moves inside a magnitude stays in the same published bucket; this page does not re-measure that as a stability rate. [3Le Pochat, Victor; Van Goethem, Tom; Tajalizadehkhoob, Samaneh; Korczy´nski, Maciej; Joosen, Wouter (2019): "Tranco: A Research-Oriented Top Sites Ranking Hardened Against Manipulation", in: Proceedings of the 26th Annual Network and Distributed System Security Symposium. (DOI)] costed attacking Alexa as cheap; it did not evaluate CrUX. Galloway et al. also did not evaluate CrUX [4Galloway, Tillson; Karakolios, Kleanthis; Ma, Zane; Perdisci, Roberto; Keromytis, Angelos D.; Antonakakis, Manos (2024): "Practical Attacks Against DNS Reputation Systems", in: Proceedings of the IEEE Symposium on Security and Privacy. (DOI)].

The figures below come from a structured extraction over 5,859 full-text papers from CCS, IMC, NDSS, PETS, USENIX Security, TheWebConf and IEEE S&P, 2010–2026. The population for this page is the 1,153 papers that drew at least one study population whose unit is websites, domains or web pages — 19.7% of the corpus, the same population as Sampling. Only those web-unit tuples are counted. Free-text sourceList is folded into vendor families by scripts/rank_fold.mjs before counting (multi-label: a string naming Tranco and Radar counts for both). Sentinel values are silence. 2025 and 2026 are provisional venue-years.

Of the 1,143 WEB papers that name any source, 764 (66.8%) name a popularity ranking and 257 (22.5%) name a custom or ad-hoc seed list — the same frame-kind fold as Sampling. This page is about the 763 of those ranking papers that name a vendor. A custom seed is a different instrument; it does not go in the table below.

763 papers (66.2%) name at least one of these vendors. Family counts do not sum to 763: 55 papers (7.2% of vendor-users) name two or more. Farsight-as-ranking: 0 papers. Radar as a named source: 4, all in 2025–2026 — it is a Tranco input, not a list people cite. The full fold, including commercial also-rans (Semrush 3, BuiltWith 2, Open PageRank 2, Ahrefs / Moz / Netcraft / Trexa 1 each) and the unnamed-top-N residue (4 strings), is on the provenance page.

Counting the exact string “Alexa” on all 5,712 papers that sampled anything finds 51; folding on WEB finds 463. The same un-folded method on ALL ranks “custom seed list” (516), Tranco (180) and Google Play (143) above Alexa (51). Google Play is 281 papers after folding /google play/i over ALL, and 0 over the 1,153 that sampled the web. Restrict to web units and fold spellings, or you will publish an app store as a website ranking.

Papers naming each list, as a share of the 1,153 in that year:

Tranco overtook Alexa in 2023, the first full year after Alexa.com died. The lag is compatible with a submission cycle; we did not read why each of those papers still named Alexa (cached CSV, inherited list, or a crawl that started before May 2022 are all possible). CrUX peaked at 9.8% in 2024 and did not keep climbing. Read 2026 as incomplete: CCS and IMC 2026 have not been held.

Of the 66 papers from 2023–2026 that still name Alexa, 32 (48.5%) state a version or date and 34 (51.5%) do not. The undated 34 cannot be pinned to a snapshot from the paper. A mirror, a cached CSV, or a list inherited from earlier work would all look like this; this corpus does not distinguish them.

Umbrella, Majestic, Radar, SimilarWeb and SecRank stay in the low single digits in every year they appear. They are specialised instruments and Tranco inputs, not a second mainstream ranking.

Scheitle et al. [2Scheitle, Quirin; Hohlfeld, Oliver; Gamba, Julien; Jelten, Jonas; Zimmermann, Torsten; Strowes, Stephen D.; Vallina-Rodriguez, Narseo (2018): "A Long Way to the Top: Significance, Structure, and Stability of Internet Top Lists", in: Proceedings of the Internet Measurement Conference 2018, pp. 478–493. Association for Computing Machinery, New York, NY, USA. (DOI) (Link)] and Xie et al. [6Xie, Qinge; Li, Frank (2024): "Crawling to the Top: An Empirical Evaluation of Top List Use", in: International Conference on Passive and Active Network Measurement, pp. 277-306.] surveyed ranking-list usage in web-measurement papers by hand. They are why this page had figures before this corpus existed. Scheitle ends in 2016-era crawls; Xie's survey of crawling papers ends around 2022 (PAM 2024; outside the seven venues). Neither includes 2023–2026, which is the window in which Tranco became the default and Alexa became residue. Alexa was not “discontinued in 2023” — that sentence was on an earlier version of this page and confused Amazon's 2022 retirement with Tranco's 2023 provider swap.

• How they were produced. One structured record per paper; each population[] tuple carries a verbatim evidence quote. The population is the extraction's unit enum (stable). The free-text sourceList is not, and is folded before counting.
• Folding. scripts/rank_fold.mjs maps a string onto every vendor it names. Alexa undercounts by 89.2% if you count the exact string “Alexa”. Farsight/DNSDB strings are a hand map of 12 spellings classified as a passive-DNS dataset, not a ranking; the report fails if a new spelling appears. Residue of unnamed “top N websites” strings: 4.
• This is not the 5,712-paper sampled population. That denominator is 97.5% of a corpus that is mostly not web measurement. Google Play, Prolific and MNIST live in it.
• Sampling's 764 “popularity-ranking” papers are a frame-kind fold, not a vendor fold; the vendor union here is 763. The one-paper gap is an unnamed top-N string that names no vendor. Sampling reports the frame kind; this page reports the vendor. Custom-seed 257 is on that page too.
• Posters. 23 of 1,153 WEB papers are posters; 10 of 763 vendor-users. Trimmed shares (posters and ≤4-page records removed, 1,113 papers) move Alexa 40.2% → 41.0% and Tranco 22.7% → 22.8%. The headline is not a silence rate.
• Venue coverage. Seven venues only. 2025 and 2026 are incomplete by construction. Xie 2024 is PAM, cited as a survey, not counted in the tables.
• Every query, the report script and its unedited output are on website_selection; corpus-level caveats are on corpus.

A methods sentence a reader can act on names, in this order:

1. Which list, with its identity — Tranco id, CrUX month, Umbrella dated zip, Majestic download date, Radar snapshot date. Not “the top 1M”.
2. What that list measures — page loads, DNS queries, cache-misses, backlinks, or an aggregate of those.
3. The draw — top-n, stratified, random, … — which is Sampling, not this page.
4. The file — archived, hashed, and deposited. See Artifacts.

Pin one dated frame, not an informal average of several daily lists. Tranco's own daily id already aggregates 30 days (Dowdall); that is a defined procedure with a permalink. CrUX is a monthly bucket snapshot — cite the month. [3Le Pochat, Victor; Van Goethem, Tom; Tajalizadehkhoob, Samaneh; Korczy´nski, Maciej; Joosen, Wouter (2019): "Tranco: A Research-Oriented Top Sites Ranking Hardened Against Manipulation", in: Proceedings of the 26th Annual Network and Distributed System Security Symposium. (DOI)] is the stability argument for that kind of aggregation, not a licence to mix unpublished daily CSVs. Do not treat Tranco as CrUX. If you can, report on more than one list: 55 of 763 ranking-users (7.2%) named two or more vendors; Ruth et al. showed CrUX and Tranco are different instruments against HTTP logs [1Ruth, Kimberly; Kumar, Deepak; Wang, Brandon; Valenta, Luke; Durumeric, Zakir (2022): "Toppling Top Lists: Evaluating the Accuracy of Popular Website Lists", in: Proceedings of the 22nd ACM Internet Measurement Conference, pp. 374–387. Association for Computing Machinery, New York, NY, USA. (DOI) (Link)], and they did not evaluate reporting both. 52.0% of papers that named a ranking vendor in this corpus stated no version on that tuple (397 of 763).

• Sampling — how to draw, sample size, unit, versioning. Assumes you have chosen a list. Custom-seed lists live there.
• Longitudinal — why a 2019 Tranco id and a 2026 Tranco id are not commensurable.
• Tranco — ids, API, the Farsight-is-default-list-only trap, pin_tranco.py.
• Cloudflare Radar — buckets are not ranks; CC BY-NC 4.0; Galloway.
• CrUX — magnitude buckets, BigQuery, country/device slices.
• SimilarWeb — the commercial panel.
• Website classification — topic labels, not popularity ranks. Alexa died as a categoriser on the same day it died as a ranking. CrUX country lists are popularity, not audience.
• IP classification — the servers a crawl connects to are mostly CDNs; geolocating them is a different question from picking the crawl's seed list.
• Artifacts — depositing the pinned list.
• corpus — how the 5,859-paper extraction was built.
• website_selection — every query on this page, the fold, the residue, the review log.

[1]

Ruth, Kimberly; Kumar, Deepak; Wang, Brandon; Valenta, Luke; Durumeric, Zakir (2022): "Toppling Top Lists: Evaluating the Accuracy of Popular Website Lists", in: Proceedings of the 22nd ACM Internet Measurement Conference, pp. 374–387. Association for Computing Machinery, New York, NY, USA. (DOI) (Link)

[2]

Scheitle, Quirin; Hohlfeld, Oliver; Gamba, Julien; Jelten, Jonas; Zimmermann, Torsten; Strowes, Stephen D.; Vallina-Rodriguez, Narseo (2018): "A Long Way to the Top: Significance, Structure, and Stability of Internet Top Lists", in: Proceedings of the Internet Measurement Conference 2018, pp. 478–493. Association for Computing Machinery, New York, NY, USA. (DOI) (Link)

[3]

Le Pochat, Victor; Van Goethem, Tom; Tajalizadehkhoob, Samaneh; Korczy´nski, Maciej; Joosen, Wouter (2019): "Tranco: A Research-Oriented Top Sites Ranking Hardened Against Manipulation", in: Proceedings of the 26th Annual Network and Distributed System Security Symposium. (DOI)

[4]

Galloway, Tillson; Karakolios, Kleanthis; Ma, Zane; Perdisci, Roberto; Keromytis, Angelos D.; Antonakakis, Manos (2024): "Practical Attacks Against DNS Reputation Systems", in: Proceedings of the IEEE Symposium on Security and Privacy. (DOI)

[5]

Xie, Qinge; Tang, Shujun; Zheng, Xiaofeng; Lin, Qingran; Liu, Baojun; Duan, Haixin; Li, Frank (2022): "Building an Open, Robust, and Stable Voting-Based Domain Top List", in: 31st USENIX Security Symposium (USENIX Security 22), pp. 625-642.

[6]

Xie, Qinge; Li, Frank (2024): "Crawling to the Top: An Empirical Evaluation of Top List Use", in: International Conference on Passive and Active Network Measurement, pp. 277-306.