RankSpeed is a search tool that does a sentiment analysis on the twittersphere / blogosphere to find the best websites, the most useful web apps, the most secure web services, etc...
You can search for any website category using tags and rank by any criteria: good, useful, easy, secure or any other keyword.
RankSpeed in the news:
"RankSpeed's Sentiment Search Engine Tracks Blogs And Twitter"
"Search by Sentiment: RankSpeed Gives Users a New Tool to Filter Results"
"This is an innovative approach in search, a search engine using sentiment data to find appropriate website content"