I think Twitter, as designed, has at least one compelling application: linking fans to stars. Fans want to know what their stars are doing and they will even pay to know. Seemingly mundane details of little or no value in peer-to-peer use of Twitter changes into precious tidbits in fans-to-star use of Twitter. To stars, it's a way to cultivate their fan community. Once the communication channel is estabilished, it can be used to syndicate attention. By attention, I mean commercials but not the old kind.
When Michael Jackson drinks Coke in TV commercial, what's the message? The message is Michael Jackson prefers Coke over Pepsi. The same message can be sent via Twitter if Michael Jackson used Twitter: I am drinking coke, he'll twit. Once the advertisers grok what's going on, they'll offer substantial money to twittering stars, not for commercials, but to simply use their product so the stars will mention their products when they twit. That's big and more effective than TV commercials in my opinion.
I haven't experienced it myself (by nature, I have never been a fan of anything) but I suspect there is a pleasing psychological effect when fans mimick stars…in real time. It's like the way crystals resonate, hives hum, and flocks line up. I am sure consumer psychologists could explain this better than I can.