According to BuiltWith, of the top million websites using content management systems (or CMSes), three systems own more than 75 percent of the total market share: WordPress, Joomla, and Drupal. (All of which are open source, by the way.) Many are likely most familiar with WordPress, which TechCrunch has covered quite a bit (and uses to power most its sites, for full disclosure). WordPress is the most popular CMS on the Web, running 62 percent of the top million websites that use a CMS, according to BuiltWith, with Joomla now ranking second at 10 percent.
There are a ton of these content management systems out there, even though the top 3 claim most of the market share. And, as BuiltWith’s roster shows, microblogging and blog publishing services are often grouped in with CMSes — as some are able to be customized into a CMS — even though their scopes tend to be far more specialized. Services like Blogger and Tumblr, to name two, are sometimes lumped in with CMSes and have attracted a lot of coverage in the press, some of which is for good reason.


