Simon Dumenco is right that Twitter is a silly waste of time and inanity (linking to a pickup since AdAge is walled) for the individual. But he's wrong in thinking it has no use, and can serve no useful purpose. While I'm not particularly interested in who's having what pizza where, doing what at what game, or telling people that I'm on my way to the supermarket or a haircut, the amalgam of all these smidgens of information can create a cloud that over time will give us a view of trends, movements, even consumer shifts. The right sifting, sorting and parsing technology could bring an understanding, perhaps mash it up with Google Maps and other similar locators of anything from geography to taste, and give us a sort of real time Megatrends/Faith Popcorn look at what we're doing and where we're headed.
Imagine knowing how many people are doing any given activity at a certain time, with what brands or people or instruments ... that's powerful, and potentially commercially valuable information. Add the information overlay of Semantic Web (or Web 3.0), and you could have an even more powerful cloud.