Good thread. I heard people on Twitter discussing DeviantArt, and while I have an account that's about a year old, it never appealed to me.
These days I only post links to my main website on Twitter. My goal over the next few months is to build a discussion forum on my Wordpress site, invite some dependable supporters to post comic and entertainment topics, and see if it becomes interesting to casual visitors.
Funny enough, Instagram used to be great for me, but I suspect (with limited evidence) that some algorithm has been throttling my hashtag visibility lately.
In the last two months, I only get 15-20 likes for content that used to get 60+ likes (and my art has only improved). That's been the biggest disappointment lately.