I've had a rocky relationship with Twitter. These days I'm on the useful side of the discussion and mostly because I can ask people for help and get answers pretty quickly. Plus, it is interesting to see what people are posting on Twitter. Using Twitbin as an ad on to Firefox definitely has enhanced my user experience. However, from a pure work standpoint, you can't live without Tweetscan.
Tweetscan allows you to search Twitter for certain keywords which at first perhaps doesn't seem like a big deal. However, if you create an RSS feed of your Tweetscan search results you now have a way of monitoring what is being said about your brand. Now you get real-time monitoring of what people are saying about your brand in 140 characters or less.
I set one up for a certain Presidential Candidate that I'm working for, not that I have that much to do with the brand, but I like to see what is being written in Twitter. So far, I haven't uncovered much that would surprise you, but Tweetscan is a piece of cake to use for monitoring the chatter of a brand.
If you are involved with a brand, setting up Tweetscans via RSS feed is a quick way to monitor what is being written online via Tweets.