San Francisco, CA, Nov 2005, Matt Mullenweg
WordPress.com
WordPress.com provides free weblog hosting (from company Automattic). It opened to November 21, 2005.
It runs WordPress MU, a version of the original software that allows people to create and manage their own weblogs without requiring the time, money and technical knowledge involved in setting up WordPress on an ordinary hosting account. It is financially supported via the use of Google Adsense banners and paid upgrades.
wordpress.org
WordPress is a self-hosted blog publishing system written in PHP. All data is stored in a MySQL database. The name WordPress was suggested by Christine Selleck, a friend of lead developer Matt Mullenweg.
The latest release of WordPress is version 2.6, released on 15 July 2008. It is distributed under the GNU General Public License version 2.
Web 2.0: Who, What, Why, How 