I'm surprised to see that it might just be an API issue. I have to think that many of LinkedIn's users don't like being rated, and having those ratings be made available without their users' opt-in. For a service like LinkedIn, dealing with people's professional reputations (and potential job prospects), this seems like it might have crossed the line in some users' minds.

All of that aside, it is a really interesting idea, although I do have concerns that Cubeduel is getting a lot of really personal (and valuable) info from this. As a project, it's very intriguing nonetheless.