Is it a good idea to provide incentives for members to participate through the use of prizes or giveaways?
Does this have the reverse effect of dissuading from participating at all once the incentives run out (since they may feel a sense of entitlement to these incentives for participation after getting used to them)?
I think mild incentives (titles, etc.) can be productive. The bigger the incentive, the more likely it is to motivate members to post junk. A prize that goes to a random choice where, say, people get one entry per post might be OK. I wouldn't think that there would be an ongoing expectation of more prizes, though chances are a few members would slow down after the contest.