Google Tag Manager and the pages it was found on
A tag manager is a container. Rather than have a developer edit the site's code every time somebody in marketing wants another script on the page, the site loads one file — Google Tag Manager — and everything else is configured through a web interface by people who never touch the repository. The name turns up in a network log because the browser has to fetch that container before it can run anything inside it. This index recorded Google Tag Manager as a company contact on 325 of the 5,294 sites measured, 6.1% of them. The surprising part is how light those pages are.
84th of 88 by page weight
The median site where Google Tag Manager was recorded contacted 5 companies over 22 network requests, with 1 of them classified as tracking. Among the 88 companies profiled in this index, that is 84th by median companies and 84th by median requests. The median number of companies contacted before the consent window closed was 4, which is 80th of 88, level with seven others.
So the tool whose entire function is to make it easy to add third parties to a page is associated here with some of the least crowded pages in the index. That is not a paradox so much as a reminder of what a container is. It is a delivery mechanism, and a delivery mechanism carries whatever it is given. Plenty of the sites that run it have given it very little.
What travels with it
The ten companies most often present alongside Google Tag Manager on those 325 sites: OneTrust on 122 of them (37.5%), Sentry on 37 (11.4%), Amazon CloudFront on 32 (9.8%), jsDelivr on 29 (8.9%), Cloudflare on 28 (8.6%), Cloudflare Analytics on 26 (8%), go-mpulse.net on 21 (6.5%), unpkg on 19 (5.8%), Adobe Fonts on 17 (5.2%) and privacy-center.org on 15 (4.6%).
Not one of the ten is an advertising company. They are content delivery and script hosting (Amazon CloudFront, jsDelivr, Cloudflare, unpkg), consent and privacy interfaces (OneTrust, privacy-center.org), error and performance monitoring (Sentry, go-mpulse.net), analytics (Cloudflare Analytics) and fonts (Adobe Fonts). Whatever tags these particular containers are delivering, the companies riding along with them are not the ad-tech names the tool's reputation would predict.
The consent picture
191 of the 325 sites carried a consent tool the crawl could detect. OneTrust was seen alongside on 122 of them, an IAB TCF banner on 41, Usercentrics on 9, Cookiebot on 7, CookieYes on 7 and Osano on 3. A site can run more than one banner, so those counts should be read as overlapping observations rather than shares of the 191.
Early contact was recorded on 311 of the 325 sites, 95.7%, which is 25th of the 88 companies here. On the median site the count of companies contacted after the consent window closed is 0 — whatever these pages were going to load, they had largely loaded it.
Who runs it
The sample includes infrastructure companies (cloudflare.com, fastly.net, workers.dev), platforms (zoom.us, paypal.com, unity3d.com, xiaomi.com), a university (mit.edu), a German portal (t-online.de) and, notably, three advertising exchanges: criteo.com, rubiconproject.com and pubmatic.com.
The individual pages are as light as the median suggests. cloudflare.com contacted 2 companies, both inside the early window, with first contact at 1,242 ms. workers.dev also contacted 2. mit.edu contacted 2. paypal.com contacted 2. The heaviest in the sample is criteo.com at 12 companies, which is what you would expect from an advertising company's own marketing site. xiaomi.com is the odd one: 9 companies, none of them inside the early window, first contact at 2,834 ms.
Reading a container's numbers
The median time to first contact on these sites was 632 ms, 55th of 88, and the fastest recorded was 83 ms. Those are ordinary figures, and ordinary is the point.
The presence of a tag manager tells you how a site's third parties are managed, not how many there are. If you want the count for a specific page rather than a median across 325, that is what a per-page measurement gives you, and it is what MurmStack was built to show.
| Site | Companies | Before consent | First contact |
|---|---|---|---|
| cloudflare.com | 2 | 2 | 1242 ms |
| fastly.net | 7 | 3 | 670 ms |
| zoom.us | 5 | 5 | 440 ms |
| workers.dev | 2 | 2 | 1063 ms |
| criteo.com | 12 | 8 | 495 ms |
| unity3d.com | 7 | 6 | 992 ms |
| xiaomi.com | 9 | 0 | 2834 ms |
| paypal.com | 2 | 2 | 1485 ms |
| rubiconproject.com | 5 | 4 | 1285 ms |
| t-online.de | 2 | 2 | 360 ms |
| mit.edu | 2 | 2 | 907 ms |
| pubmatic.com | 6 | 6 | 191 ms |
| Tool | Sites |
|---|---|
| OneTrust | 122 |
| IAB TCF consent tool | 41 |
| Usercentrics | 9 |
| Cookiebot | 7 |
| CookieYes | 7 |
| Osano | 3 |
The six most common are listed. The remaining 2 of 191 sites with a banner carry something outside that six. One tool is recorded per site, so these counts never overlap.
Seen on the same pages
Companies most often contacted by the same sites. Co-presence only — the crawl records what arrived, not who called whom.
- OneTrustTogether on 122 of these sites
- SentryTogether on 37 of these sites
- Amazon CloudFrontTogether on 32 of these sites
- jsDelivrTogether on 29 of these sites
- CloudflareTogether on 28 of these sites
- Cloudflare AnalyticsTogether on 26 of these sites
- go-mpulse.netTogether on 21 of these sites
- unpkgTogether on 19 of these sites
Questions
What does Google Tag Manager actually do?
It loads a container that a site's marketing team fills through a web interface. Scripts can be added, changed or removed without a code deployment, which is why so many sites use it and why its own presence says nothing about what it is delivering.
Does a site running Google Tag Manager contact more companies?
Not in this index. The median page where it was recorded contacted 5 companies over 22 requests, which places it 84th of the 88 companies profiled here on both measures.
How many of these sites had a company contacted before the banner could be answered?
311 of 325, or 95.7%. That share ranks 25th of the 88 companies in this index, so it is common but far from the highest here.
Which consent tool appears most often on the same pages?
OneTrust, seen on 122 of the 325 sites. 191 of the sites carried some detectable consent tool.
Why is this different from the framework detection for the same name?
This entry counts a company contacted by the browser. Detecting the tag manager as part of a site's stack is a separate measurement with its own page, and the two answer different questions.