I became a fan of Twitter only recently, and am seeing its value for professional networking. No so with Facebook, which I use on a more social level. But that's just my preference.

At some point, Twitter will have to show a profit, and that will involve some changes to what we see on the screen and how our data is used. From where I sit, Facebook has done a reasonable job of monetizing a social net without poisoning the overall environment (Beacon notwithstanding).