Even though you explicitly state that you win based on who makes the most noteworthy posts, I am pretty sure that a lot of spam will be generated by this campaign. Might be smarter to accept people based on their previous posts (but that is my personal opinion). I do recommend you to use escrow. A lot of people got screwed in the past, which makes them wary of joining new signature campaigns. If you have any questions about that, just send me a PM