According to the fourth annual study by Water&Stone, WordPress, Joomla and Drupal are the three most popular among 20 free web content management systems, narrowed down from an initial list of 35. 
Among the .NET-based CMS players, DotNetNuke dominates, while among Java-based CMSes, Liferay and Alfresco are the joint leaders. The authors conclusion was that the WordPress Web Design capabilities outshone its competitors
The survey also picked out Concrete5 as an open source CMS to watch saying “no other system came close to showing the growth seen by Concrete5” though it still lagged the top 3 systems in terms of market share. At the other end of the scale, the survey expresses concern for e107, Movable Type, TextPattern and Xoops, describing them as “potentially at risk” of leaving the top 20 for various reasons.
The survey combines questionnaire data with the analysis of various metrics to come to its conclusions. The main criteria for the analysis for each distribution were: the number of downloads, number of installations, support services by third parties, and books available about each CMS. Another criterion was the strength of the brand, specifically tied to the visibility in search engines, the popularity of the project site, the brand awareness and visibility in social networks. .
