See who you mention on Twitter,

SpellBound for Twitter This Firefox add-on enables you to spell check your Tweets! Works much better than your built-in spell-checker, Just one click install. jundle.com/spellbound-spellcheck-your-tweets/ to Visit spell-bound-for-twitter is no longer online.

This shows Exhaustive list of all twitter applications ranked according to the number of tweets posted from them.

This provides extensive brand, product, and topic tracking over time,

TwitterTopTwenty.com  is a top 20 list of everything on twitter including stats, users, and trends.

This is one of the first, enterprise grade end-to-end campaign management, analytics and community engagement solution.

Finds ideas and opinions in tweets, blogs, and links and provides social publishing tools like multimedia slideshows, testimonial widgets, and conversation starters. Uses sentiment analytics for emotion grading and NLP for topic discovery. Click Here to visit Cuesense

PayPerTweet connects advertisers to Twitter users in a way that allows the user to be both, selective and genuine. That is the most feasible thing