Open source blogging platform WordPress has reached an important milestone: It powers more than 50 million websites, about half of which are hosted on WordPress.com.
Also, more than 287 million people view more than 2.5 billion pages on WordPress.com each month and, on an average day, WordPress.com users create about 500,000 new posts and 400,000 new comments, according to WordPress’ official stats.
Recently, WordPress competitor Tumblr surpassed 20 million blogs, passing WordPress.com in terms of the number of blogs hosted on the platform.
However, unlike Tumblr, WordPress lets users install and use the platform on their own web host. Due to the simplicity and versatility of the platform, WordPress isn’t only used to power blogs, it can also be used for running various types of personal, business and community websites.
Article source: http://mashable.com/2011/07/11/wordpress-50-million-websites/