Recently, we’ve been wondering about the adoption of tag management systems (TMS) across different industries. We wrote a few posts a while back about the airline and auto industries adoption (or lack thereof) of tag management.

This time, we decided to figure out the most popular tag management systems across the top 500 ecommerce sites. To do this, we used the 2014 Internet Retailer Top 500 Guide and Tag Inspector to identify the tag management systems used (if any) and analytics tools (if any) by each website.

We came across a couple of very interesting findings that you’re going to want to read. So, carry on!

For information on the methodology behind the data collection and visualization in this post, click here.



Finding #1: The first finding that jumped out to us was the number of ecommerce sites that were not using a tag management system. Over 41% of the websites scanned did not use a tag management system!

With the amount of data and the number of tools used on ecommerce websites, there is clearly an opportunity for tag management systems to unify and centralize data collection.

Finding #2: The next interesting finding was that 14% of ecommerce sites scanned had multiple tag management systems present.

This is interesting for a few reasons:

  1. Most TMS are paid or come bundled with another paid tool, so that could get expensive
  2. One of the main ideas behind tag management is to consolidate your tags. Adding an additional TMS to your site makes tag management more convoluted.
  3. TMS typically use similar but different syntax for collecting data (the data layer). For example, Tealium recommends using var utag_data, while Google Tag Manager recommends using dataLayer. Having your developers code for two different syntaxes, or your marketing team configure one tool to read the other’s syntax, is confusing as the least.

Now, I will point out that it’s very possible many of these ecommerce sites are only using one TMS. There might be iFrames or plugins included on the site from a third party that has injected their own TMS for tracking purposes. I’ve run into this before on sites (and it’s more prevalent than you would think).

However, for the sites with multiple TMS present, we can’t easily identify the main TMS being used. This is why we decided to lump them into their own category, “Multiple Systems Found”.

Finding #3: Google Tag Manager is used the most by the Top 500 ecommerce sites.

If we exclude the 65 websites that use multiple systems (because we don’t know what their main TMS is), there are 399 websites left. Of those sites, GTM is present on 79, for a whopping ~20%!

Popularity of Tag Management Systems

Note: Only 464 websites are represented in this chart. Feel free to mouse over each bar for an exact count.


 Tag Management Systems by Ecommerce Site

Link to full visualization

Note: The size of the yellow nodes represent the count of websites using that specific tag management system.

Not all ecommerce sites are represented in this visualization. Any website that uses multiple tag management systems was excluded. This left 399 websites that use only one TMS solution (or no TMS solution).



The data for these visualizations came from scans of the Top 500 Ecommerce Websites. The list of Top 500 Ecommerce Websites came from the 2014 Internet Retailer Top 500 Guide.

The bar chart visualization came from Google Sheets and the node visualization came from Google Fusion Tables.

Only 464/500 scans were successful. Unsuccessful scans most likely were due to websites blocking crawlers like Tag Inspector’s.

We scanned 100 pages, at random, for each website and Tag Inspector reported on the tag management systems that were found on those random 100 pages.

We split out TagMan and Ensighten in our data – even though Ensighten purchased TagMan in 2014. This was because these sites were still using the TagMan code and not the Ensighten code.

Assumptions: We made a few assumptions with our scans:

  1. If a tag management system is present on 100 pages of the site, we assumed the sites uses that TMS.
  2. If multiple tag management systems are present on the site, we assumed they used one or both of the tag management systems.
  3. The reports were ran in March and the sites could have changed since then.
  4. It’s also possible that a site includes a tag management system that Tag Inspector didn’t pick up in the random 100 pages we scanned.

*DISCLAIMER: All data from this post came from Tag Inspector scans. We did not work with any tag management vendors to discuss their clients or who uses their product. The data is publicly available, by either viewing the source code of a website page and searching for the tag management system tags or using a plugin like Ghostery or Tag Explorer to identify the tags on the site. 

If you feel our report has any errors, feel free to email me at agibson [at]


Get Your Free Tag Inspector Account Now