I was once a heavy quora user. Here's what drove me away (I do still use it but I no longer 'hang out' there): the overwhelming pretentiousness and self-righteousness of many within the very early core userbase who, because I was in that early group, dominate my feed (don't know if they dominate for others...). You can only read so many "what does it feel like to be dumb" or "if i went to Harvard how should I respond to 'where did you go to school?' without offending the asker?" without rolling your eyes and writing the entire thing off as a circle-jerk for the self-appointed hipster elite. These people suck and unfortunately quora has rewarded them with upvotes and therefore influence. Otherwise I think the site is great and useful for very niche/obscure questions that google cannot answer well.