In January 2003, Mullenweg and Mike Little started WordPress from the b2 codebase. They were soon joined by original b2 developer Michel Valdrighi. Mullenweg was 19 years old, and a freshman at the University of Houston at the time. He co-founded the Global Multimedia Protocols Group (GMPG) in March 2004 with Eric Meyer and Tantek Çelik. GMPG wrote the first of the Microformats. In April 2004, with fellow WordPress developer, they launched Ping-O-Matic, a hub for notifying blog search engines like Technorati about blog updates. The following month, WordPress competitor Movable Type announced a radical price change, driving thousands of users to seek another blogging platform; this is widely seen as the tipping point for WordPress.