http://www.technorati.com
Technorati is an Internet search engine dedicated to the world of
weblogs (or blogs). As of December 2005, Technorati indexes over 23
million weblogs. Technorati was founded by Dave Sifry and is
headquartered in San Francisco, California, USA. Tantek Çelik is
Chief Technologist.
Open Source
Technorati uses and contributes to open source software. Technorati
has an active developer community, many of them from open source
culture. Sifry himself is a major open source advocate. Technorati
includes a public developer's wiki, where developers and
contributors collaborate, as well as various open APIs.