At first glance when I first discovered Twitter (in the very beginning) I also thought there wasn't much use for it (based on the question "What are you doing?). But Twitter is one of those things that you need to get involved in to understand (to actually get it!) and take value from it. It's all in how you use it and, most importantly, in who you follow.
Here's a guide to Twitter for those of you who can't see usefulness in it, it's a good place to get started and start enjoying Twitter:
The Big Juicy Twitter Guide | Caroline Middlebrook
And to those of you who DO enjoy Twitter, here's where you can follow me:
Twitter / PatriciaMuller