I used to contribute a ton to Stack Overflow at the beginning in 2009 and 2010 and then stopped cold turkey. One of the senior product execs emailed me to see what turned me off.

What killed it for me was community moderation. People who cannot contribute with quality content will attempt to contribute by improperly and excessively applying their opinion of what is allowed.

Unfortunately it happens to every online technical community once they become popular enough. I even see it happening on HN.