From their site: Technorati is the recognized authority on what is happening on the World Live Web, right now. The Live Web is the dynamic and always-updating portion of the Web. We search, surface, and organize blogs and the other forms of independent, user-generated content (photos, videos, voting, etc.) increasingly referred to as citizen media.
Many APIs eventually find their way to the ProgrammableWeb deadpool. They end up there for various reasons: no business model, replaced by a newer service or ceased being useful. The most popular of these dead APIs are predominantly from two big tech firms: Google and Yahoo. Search and mapping make up the bulk of the functionality behind these 12 popular--but no longer available--APIs.
Once the mouthpiece and aggregator of the blogosphere, Technorati lost its luster long ago. And now it's lost its API, too. The developer page promises a new API but also makes one thing clear: the old one is gone.