Social Mention is a social media search engine that searches user-generated content such as blogs, comments, bookmarks, events, news, videos, and micro-blogging services.
It allows you to easily track what people are saying about you, your company, a new product, or any topic across the webs social media landscape in real-time.
Search results are aggregated from numerous popular social media sources, including Google blog search, Twitter, Delicious, FriendFeed, Flickr, Digg, YouTube etc. and remixed as a single stream of information.'