I have received bonus points every few months for creating a popular thread. I've also noticed that I sometimes receive 1.5 points per thanks, but don't know how that happens or why. In any case, I still haven't figured out how to cash these points in for prizes or rewards, though.
There are people who frequent the OT section with only a few posts (because OT posts don't count) but thousands of points because they posted lots of pictures to a certain now-retired eye candy thread.....