Facheache with their enforced algorithms, in ability to display the posts in a chronological order anymore, ads, suggested posts and all that crap has turned a lot of people off - but it does better for somethings than twitter, Instagram & snap with the groups, events & chat being inbuilt.
But it isn't the "young" platform it once was.... It's kinda turning a bit into myspace in that respect! (Google killed off G+ in April)
As said though, I find that faceache just doesn't hold the info/knowledge that a forum does - I'm sure you can get in contact with people and DM them to have a chat, but people don't tend to share the lessons sides of things out. so I for one and very glad this place is still here - who knows soon I might be able to actually share summit about the ZS as well