Pay per activity is a terrible idea... Users that post more are worth more for a signature campaign --> more ad's placed
Not to mention it encourages buying accounts, if you only have to post say 50 times to receive the payout (which is likely ~1/2 the payout size for someone that posts a decent amount per month) than it would make the multi dipping signature users job much easier, just post 50x on each account and receive full payout on all of them instead of posting several hundred times to reach better payout.
I was planning on switching my signature campaign after this month anyways, to advertise my own sites.
Thanks again Stunna for encouraging users to continue coming to this site, yes they might post just for the $, but most people (at least hopefully

) aren't posting mindless crap.
Cheers