I new a democrat would go after Craiglist sooner or later. Craigslist is simply to free to be allowed to stand as it exists and has gained way to much exposure. No politician can become aware of such a thing without having an urge to screw it up. This is just the first step. They are looking for a way to gain power and influence over it and, by the nature of a politican having power and influence over something, to destroy it.
The prostitution angle is a red herring. Nobody cares about prostitution.
It will be interesting to see what deal the devil will offer.