--snipe--
Yes, maybe a test it's the better thing. Block the signature or limit the characters and see if the spam will end or not.. (I guess : yes of course !).
On the other side,most of the Gambling sites or any new bitcoin related Start-ups approach the forum for advertisement of their products.Vaguely,Signature Campaigns are the easiest ways to do it (apart from promo giveaways).Do you think such Start-ups would still approach if they're unlikely to get as much exposure after stopping the signature campaigns?