I still use Google+ together with those listed above by Colin, Facebook has lost it's appeal even though still use it.
Twitter for news and quick posting, best place for news.
Medium for exceptional quality and in-depth information on occasion.
You Tube, unfortunately you lose time, find some interesting topics and debates.
Instagram not so often.
Pinterest on a rare occasion.
Steemit has become my main source of social interaction, good balance of photography, quality content and great reading matter.