I'm a bit late to the conversation on this (had no time over the last day+), but I want to comment on Twitter, and how I see it as a somewhat different entity than the other social media platforms being discussed.
I see it more as a tool than as a place to spend time or even as a place to communicate. I used to look down on it, but realized too much of a window and perspective on to marginalized communities was present on it to be ignored, so I joined. It has been invaluable. Utterly invaluable, as a political tool, and as a door in to socio-political, philosophical, and critical/theoretical avenues I might have missed. That it serves as an announcement platform for musical or mountain/climbing related stuff for me is ancillary.
It's also become a useful activist tool.
An example: some of you might be aware of the @slpng_giants campaign to defund Breitbart of ad revenue via advertisers who were not aware they were advertising on it via AdSource, AdWords, Google, etc.
Kellogg's was the famous start, but hundreds of companies have pulled their advertising as a result. I myself have gotten Vintage King to blacklist Breitbart, some other companies probably not known here, and, as of yesterday, Blue Shield California. Hundreds more people are making the small efforts required to get it to work, and it's having an effect.
So there's that, in favor of Twitter.
FB is mostly a sad, degenerating place of horror.
But I persist.
Mostly for the friends' pictures of kids.