I'm not entirely sure what you mean by "vouches". Sometimes when buying or selling, I will look at a poster's history in the discussion threads here at Bladeforums. It gives me a general idea of who they are, if they get along well with others, etc. I guess that's a kind of community "vouch". It may sway my decision as to whether to do business with them. Still has nothing to do with using Goods & Services on Paypal, though.