Twitter Webapp Social Media Marketing - UnTweeps - Unfollow Twitter users who don't tweet often enough.
haven't twittered

CoTweet™ - How business does Twitter
CoTweet allows multiple people to communicate through corporate Twitter accounts and stay in sync while doing so.

Presenting with Twitter
#in (via @jeanlucr) Comment faire une bonne présentation en s'appuyant, en plus, sur Twitter

The Twitter Times
Un résumé d'information à partir des préférences des suivis.

Everything you ever wanted to know about Twitter | Charles Curle Design
Read on for a PhD in Twitter...

FREE PowerPoint Twitter Tools | SAP Web 2.0
Ever wanted to make presentations a more interactive, Web 2.0 experience? A prototype version of the PowerPoint Twitter Tools is now available for testing. Created using SAP BusinessObjects Xcelsius (but requiring only PowerPoint for Windows and Adobe...

TRAACKR
Could be useful for a quick read on influentials in a given area. Not picking up anything at a glance that other tools don't do, however... "Traackr measures online influence on the social web. We use a methodical approach to find meaning in...

Your Twitter Karma
Now allows login via Twitter auth. Can bulk block, follow, unfollow twitter users. Useful also to see who is following you, tweeting recently but you haven't followed back yet.

Google Alerts for Twitter Lists - Listiti.com
Useful, like google alerts but for twitter lists

How Twitter is Changing the Internet
For news to travel the world used to take day and even weeks now only takes a tweet. Twitter is making the most radical shift in media and networking in recent years. Twitter is quickly becoming the central real-time hub that serves to enhance every...

MustExist | What Twitter lists say about you?
When people add you to Twitter lists, they tag you.May be you are on "Cool Peeps I Know", "Uber-Geeks", or "Marketing Aces" ...or, may be, you somehow ended up on someone's "People to Avoid".What do Twitter...