Back when twitter was really buzzing, I thought a web client was a great idea. I built one and forgot about it. I have ironed out some bugs and it's working at http://twitexplode.com
Apart from the narcissism points, what else can I do with it?
Add analytics. I'm not sure how, but I believe there is a market out there for twitter tools to measure <i>stuff</i> in searches/twitter streams. Integrated with a client sort of makes sense to me. But I'm no social marketer, so I may be way off.