There are a few obvious way they can make some money. Though it almost seems like they are trying to create a massive following and get people highly addicted.

Like a crack dealer handing out free samples for a week because he knows he'll have a customer for life.

Yes greggrss, Twitter totally has a useful place on the web and for wireless. It's really great for mobility. There was one incident I remember a few months ago. A woman was in the process of giving birth, and all the while twittering about it from her cell phone.

The trick is to really get the average, non-savvy user to stick to it. That I think is where the real challenge will be.