Facebook is my main one. Lots of family and old (and new) friends that I keep up with there. Plus it's where our local sale sites are (no Craigs list here) and I belong to several scrapbook groups on there which I keep up with. And my current 6x6 paper class is all on a closed Facebook group.
I also have Snapchat because my grandsons in North Carolina and my DD use it a lot.
Creating memories, one page at a time.