Generally ES's, who seem to think that other people actually care about what happens in every moment of their existence, especially to do with their current relationship, which has now turned "complicated" (broke up), and the fact they had strawberry jam on their toast this morning rather than peanut butter. To answer your question more directly: extroverts, simply because they can feel objectively valued externally e.i, through friend count, likes and comments etc (and that would probably give them energy), as well as the fact they would be more likely to want to interact with others even when not physically out with them.
I'm not a big fan of Facebook myself but I do check it once in a while to keep up with some of my friends and relatives who use it as a primary means of communication.
I know both introverts and extraverts who are Facebook obsessed for different reasons.
One of my facebook friends is eNFP (tested). She's one of those shy extravert types. She is energized by social interaction but shy about approaching people. She is not shy at all on Facebook, and spills out her life story so to speak. I eventually had to remove her from my news feed because it was just getting to be too much.
Another Facebook friend who posts heavily, I'm guessing is ISTJ. I think for him, it isn't so much the social interaction that draws him as much as the fact that it's a fun diversion. He enjoys sharing funny photos, news articles, and occasionally discusses political things. His posts, although too much at times are more amusing so I keep him in my feed.
5w6 or 9w1 sp/so/sx, I think