The last straw for LJ for me was when they made any mention of queerness illegal so as to conform to the laws of their new home country. I logged out and never logged in again. I still get badly-translated email about anniversary gifts for my various 13-year-old accounts now and then.
I have a DW account but it lies fallow, mostly because I could never get the auto-crossposter plugin to work on my Wordpress site.
September came for Reddit long, long ago. Personally I stay way the hell off of any popular subreddit because they’re just a total wasteland. And September comes for the small subreddits now and then, too - they’ll grow too big, the active mods get overwhelmed, and it starts to turn into 4chan. And I unsubscribe. If I’m lucky I hear about the mods starting up a new offshoot subreddit that’s trying to be small, relatively quiet, and aggressively unpopular.