Twitter: The three biggest haters and ragebaiters in the game obviously use Twitter. Seven and Doorman do it for the love of the game while Yamato is effortlessly like that.
Instagram: Lash and shiv are thirstposters, mina uses it to showcase her latest fashion pieces, paradox uses it to tease upcoming exhibits and Celeste runs the circus insta page (tho she never appears in it herself).
Facebook: the old people are there because they are old, while McGinnis, Bebop and Abrams are the sort of people to have one obligatory social media that they check once a month. Venator catfishes vampires on Facebook because vampires are old.
Tumblr: Paige and Graves are obvious, silver is one of those 35 year old lesbians that use Tumblr to complain about their lives and beef with people. Henry and Savannah do nothing but vaguepost about each other. Nobody can tell which blog is who's.
Pinterest is the ultimate old lady app.
Whatsapp: Everybody here seems like they use social media in the most utilitarian way possible.
Discord: idk, young people. Pocket definitely seems like a discord user though.
Reddit: I initially considered putting him as a Twitter user, but then I realized that Billy is filled with such conviction and a need to be right that he must be a redditor.
Feetfinder: Vyper pretends the feet belong to Lash while drifter sells his victims feet pics (just for fun, he doesn't even use the money. There's millions in that account).
Doesn't use social media: All of these people just seem like the sort to either disavow it, don't know what it is or find it useless for them.