It depends but we researched this quite a bit at Stack Overflow. TLDR; it was a very bad motivator to create high quality content and generally turned people off. Example: Being a nice neighbor, you shovel your neighbors driveway for a month. Afterwards, your neighbor shows up and gives you 50 cents.

It often makes you examine how little value you are receiving for good content, and wasn’t the reason you created that good content to begin with.