Yes something like 50 posts per month and each member status has a set rate. That way the spamming stops and people still get paid. Since each person costs less he could have more participants...and get the same exposure minus the endless spam.
While it should create a lot less spam, the cost per impression would be higher for Stunna.
Those existing campaigns pay about 0.1 btc for 50 posts, and so Stunna will probably need to pay the same rate as well (=0.002 per post if everyone make exactly 50 posts), which will be a lot higher than Stunna 0.0006 per post rate in his mind.
https://bitcointalk.org/index.php?topic=291387.msg9291093#msg9291093