I also think the benefits they hope to learn about character, associates, work ethic, should be pretty evident from interviews with coaches, trainers, and teammates. If a team knows how do scout properly and devotes the proper resources to this critical service, they shouldn't need twitter or facespace or mybook.
You really think so? How many coaches, trainers, teammates, etc. are going to tell the real unsugar-coated truth about somebody? Coaches and trainers know the more kids their programs get in the pros, the better off they are. I feel like coaches/trainers are only going to say a few basic things (basically the same thing most people say about others):
He's the greatest [fill in the blank] I've ever had in X years.
Or
He's good kid and has a great chance to make it in the pros if he continues to work hard and stays focus.
Is the coach/trainer really going to say things like: the kid doesn't have a good work ethic, I'm pretty sure he's using steriods and recreational drugs, he was a nightmare when he was here, I'm just glad he's leaving my program.
As for teammates, I don't see the majority of them saying negative things, unless there's a real grudge.
When it comes down to it for sports, teams are investing millions, and probably tens of millions, and potentially hundreds of million dollars in a player. When you're doing that, I would want all the info I can possible have about someone. Not saying I'd give it much weight, but the character profile you could draw up from tweets might be able to help tell you if the kid will re-sign after his rookie deal, or will demand to be traded in a few years, or only wants to live in NYC, LA, or Miami.