<zaroth>: I'm not sure why you were downvoted, so have an upvote.

Not saying I entirely agree with you -- calling it a "tax" is incendiary and no more accurate than saying "why do we need to pay a 10% tax to grocery stores or Amazon?" -- but your broader point is an interesting one.

I'm pessimistic about this application of p2p discovery in the short term, but in the longer term (>7 years) you may well be right. The short/medium-term problem, and this goes back to 1990s discussions among cypherpunks about anonymous reputation systems, is that those "honest reviews" are attractive targets for gaming.