I haven't contributed to any of their sites since the ridiculous deletion of OnStartups due to the opinion of one moderator (If I remember correctly, which is vague now). I don't care that I lost half my rep. Some people had put really lengthy, researched, answers and a valuable resource was just rm'd.
There's far too many silos. Sure separate maths from games from Java. You have a tech question, is it webmaster, server fault, super user, or what? Seems like there's a very slim chance of getting it right first time. Sometimes it's the remit of several but none seem to want it. Or get marked as duplicate when it's fundamentally different to the marked duplicate.
Some of the subjective questions have attracted the best, or most useful, answers. Even when they've survived years they still sometimes get deleted.
Stack Exchange isn't worth the effort any more.