We know how successful karma/reputation systems are at encouraging users to contribute good content. The unexpected thing I've learned from Stack Overflow is th

We know how successful karma/reputation systems are at encouraging users to contribute good content. The unexpected thing I've learned from Stack Overflow is that the reputation system, when it doesn't work as expected, can also be demotivating. My personal experience has been mixed with regards to how successfully my answers are accepted. On multiple occasions, I've answered questions first, only to have another answer accepted that contained the same content as mine but was posted hours later. I don't know if this is a common experience or if my sample size is too small. In any case it's a bit frustrating.