Hootsuite - manage multiple Twitter profiles, add multiple editors to a profile without password hassle, pre-schedule tweets, measure your success, and a tweet bookmarklet.
Twimailer - you know when you get an email notification of a new person who is following you, well the email doesn’t tell you anything about that person. In comes TwiMailer, once you join up it gives you a unique email which you have to enter in your Twitter profile settings. Now when you get an email of a new follower, it displays their bio, avatar, their following and follower stats, and a stream of their latest tweets, and a link to follow them back…all that’s missing is a “block” or “remove” link. I wonder if this could also hook up with Qwitter.
Top Twitter Friends - a cool social graph tools where you can: see your conversations, see your towns social network, see people who talk about you.