Meet the tracking companies that follow you around the internet

Jona Pomerance

Hi, I’m Jona, currently part of the design team as an intern. In this week’s post, I’ll be taking a closer look at the tracking services and companies that invisibly accompany us across much of the internet.

Considering the cookie consent banners that have come to grace our screens on a daily basis, it might not come as a surprise that companies are interested in extracting data from your online activities, and that browsing the internet is not exactly a private affair. Still, it is hard to grasp how this data collection actually happens and who is involved. In this post, I want to take a closer look at web tracking and the companies behind it.

One website, many connections

When you visit a website, your web browser typically doesn’t just connect to the domain visible in the address bar, but to a variety of external services as well. Some of them might be required for the website’s basic functions, while others might serve advertisements, gather visitor statistics, or display embedded content from social media.

All of these connections have one thing in common: They give the parties on the other side an opportunity to collect data. Those parties can also use a variety of mechanisms to tell your connection apart from others, including storing browser cookies, loading invisible images (“tracking pixels”), and generating unique fingerprints from your device- and system-specific settings.

The chart below shows the tracking services that have been observed on some of the web’s most popular websites. (Along with the other charts in this post, this one uses data collected by Ghostery, an ad-blocking browser plugin, and published in the open-source tracker database WhoTracks.Me.)

Amazon’s 26 trackers, two thirds of which are used for advertising, already make up a considerable number. Yet it is not uncommon for websites to embed two, three, or even four times as many. Among the 100 websites most frequented by Ghostery users, the UK’s Daily Mail takes the top spot with a staggering 125 unique trackers observed.

One tracker, many websites

While the thought of third-party services picking up on our website visits might already be alarming, things get even more problematic when the same services reappear across multiple sites. The mechanisms that trackers use to tell your connection apart from others allow them to recognize they've seen you before. This enables them to follow users across the internet, building personal profiles that increase in accuracy the more data from different websites they're able to link together. These profiles might then be sold to ad networks for targeted advertising.

As this chart shows, “multiple websites” doesn't quite express just how widespread some trackers are. Google Static, for example, is active on over 9,000 of the internet's most popular 10,000 sites.

One company, many trackers

But looking at the reach of individual trackers still doesn't paint a full picture. You might have noticed it's not just the previous chart's top slot that belongs to a Google service — eight of the top ten trackers are operated by the California company. By aggregating tracking data from all of its services, Google can increase its reach even further. This makes it virtually inescapable, with just 62 of the top 10,000 websites not establishing a connection to one of Google’s servers.

Counting the number of websites that tracking services and companies have been observed on is not the only way to measure their reach. Another option is to consider how much of the web's total traffic passes by each tracker. This accounts for the fact that the #1 website generates much more traffic than the #10,000, but also that the millions of even smaller websites still add up to a sizable share of total browsing activity. For this reason, the lighter bars in the chart above show tracking companies' reach as a percentage of all web traffic.

One web, many companies

This scatterplot lets you explore 500 tracking companies with the highest reach across both metrics. Hover any point to get more information about a company, including its location and details of its business model.

Ways to browse more privately

While it's impossible to browse the web without leaving any traces, there are ways to significantly reduce the data that trackers can collect.

Configuring your browser to block third-party cookies (already the standard setting for Firefox and Safari) can limit tracking mechanisms that rely on them, and plugins like uBlock Origin can protect you from many of the trackers shown in this post. And if you're using Chrome or Google Search, it might be worth considering privacy-preserving alternatives like Firefox and DuckDuckGo.

Here are some resources for more information:

• Privacy on the Web – An overview article on web privacy by Mozilla, the company behind Firefox
• Cover Your Tracks – A test to see how vulnerable your browser is to fingerprinting, provided by the Electronic Frontier Foundation
• This Article Is Spying on You – A New York Times article about tracking on news websites, part of its series “The Privacy Project”
• Privacy Guides – A non-profit project publishing recommendations surrounding web privacy
• Awesome Privacy – A crowd-sourced list of digital apps and services that respect users’ privacy
• WhoTracks.Me – A web tracker directory based on the same data used for this post

Thanks for reading, and we’ll see you next Thursday for a Weekly Chart from Erle!

---

Jona Pomerance

(he/him, @jona@vis.social) is an interface design intern on Datawrapper’s design team. Away from the screen, you can find him commenting on beautiful letterforms and incorrect apostrophes in Berlin’s cityscape, learning Asian languages, playing badminton, and caring for his house plants.

Liked this article? Maybe your friends will too:

Twitter Facebook