I for one would NOT use this service. There is a lot of mistrust in this industry, and no one wants to potentially give away an idea for the sake of third party market analysis that isn't that well known or confidential.
We're trying to build the same model, but hoping (and assuming) that people are quicker to give their interest, and sign up as an early adopter for an idea if its built, than to open up their wallets to new ideas.
As far as giving away their idea, we're definitely going to try to do what we can to protect those posting from a legal side, or at least offer a VERY convenient way to say "hey! this was mine on this day"
Don't you generally have to show something off (as in hey, look what I'm in the process of, care to join?) with those to get backing? This is just pitching an idea, right?
Not to piss on your parade, but you can't protect anything.