Online advertising, visitor tracking and data collection are ubiquitous on the Web as a lot of content and many services are offered for free and providing them costs money.

Users usually appreciate free content and services, but are not fond of many forms of advertising like flash banners or pop-ups. Moreover, privacy and security are concerns. Big companies like Google or Facebook track users across many different sites and gather extensive information about them. Last but not least loading the additional resources to display ads and track visitors makes many Websites terribly slow, especially for mobile users.

Browser extensions like uBlock block many of those ad and tracking requests and display the number of blocked requests. On some pages this number can get offensively high.

I was curious to compare some of the top Websites based on how much blocking is going on and created the chart below that shows the numbers for 50 of the most linked to domains based on the mozRank top 500 listing. I manually collected the numbers browsing the sites in Chrome's incognito mode without being logged in anywhere.

The media sites on top stand out. This should not be a surprise as news sites are often plastered with ads. Only 5 sites have no requests blocked. Wikipedia as expected, statcounter not so much and the URL shorteners goo.gl and t.co merely serve to redirect users.

Facebook and other social networks with low numbers like Twitter, Instagram and Linkedin gather most information from logged in users.

I was a bit surprised seeing w3.org in the upper third. All of their blocked requests are a result from using piwik for visitor tracking, which I consider completely legitimate.

Operating Websites myself I'm interested to see what content people view and like and think that relevant ads can provide value to users. Nonetheless, I can see that users get annoyed when there are literally more ads than content and want to avoid extensive tracking. Less would probably be more in many cases for both the operators and the users.