Alexa and SimilarWeb rank Wikipedia as the 7th and 9th most visited site on the web, so the visit statistics produced by the foundation are a good proxy for getting data on the most popular platforms on the web. The chart above shows the visits by OS family. As you can see, Windows 7 is the most popular desktop OS, but mobile operating systems (Android and iOS) are responsible for almost 40% of the visits to those sites.