Technorati is an Internet search engine for searching blogs, competing with Google, Yahoo and IceRocket. As of December 2006, Technorati indexes over 55 million weblogs.

Technorati was founded by Dave Sifry and its headquarters are in San Francisco, California, USA. Tantek Çelik is the site's Chief Technologist.

Technorati uses and contributes to open source software. Technorati has an active software developer community, many of them from open-source culture. Sifry is a major open-source advocate, and was a founder of LinuxCare and later of Wi-Fi access point software developer Sputnik.

Technorati is blocked in China.

From the Technoratie Blog:

When we rolled out tags 2 years ago, only a few other sites had implemented them as a part of their service. Now every major blog publishing platform includes them - but they're quickly becoming a key publishing feature across the many other forms of citizen media. That's right: tags aren't just for bloggers anymore. You can tag photos (try Flickr), videos (YouTube, Revver, Blip.TV), games, podcasts, songs, or even a person! Technorati likewise is increasingly going beyond blogs to present to you the best of the Live Web, no matter what the media type might be. Because of our changes, tags are a better way than ever for citizen publishers of all kinds to categorize their work, making it all the more visible to people who want to find their stuff.

And, with the launch of our new Tag Pages, we've improved the way that you can check out the Live Web, too. A Technorati Tag Page shows you everything in the known universe (blogs, videos, photos, podcasts, music, people) tagged with your topic or interests, all in one place. .....

The beauty of tags is that they're metadata: data about data. What does that mean? Tags actually describe their subject, as opposed to, say, keywords, which just occur within them. We think tags are becoming popular because on the Live Web, categories and topics are just as useful than keywords for describing and finding content, especially when that content doesn't necessarily contain lots of relevant text (photos, videos, songs and so on). So, the next time you see tags around a good blog post (or video or game), click on it! And next time you're at www.technorati.com , try building a Tag Page on the topic of your choosing. It's a great way to find what's hot - right now - across the Live Web.