Maybe I’ll write a canonverse fic where Team Free Will discovers Tumblr, and only Sam has enough self-control to curb the number of hours he spends on it. Meanwhile, Dean and Cas pretty much start blogging aggressively, and Dean gets angry because what the hell, why did he even bother with a desktop theme if it doesn’t show up on Mobile why, Cas. And Cas doesn’t care as much about his theme until he finds a cute, vintage-y bee wallpaper image on Google and promptly installs it as his header. What he does pay more attention to are his tags, and he spends 45 minutes hemming and hawing before deciding to go with #dean look (Sam snorts). Dean, on the other hand, finds it impossible to make up his mind, so he rotates between #chuckles, #huggy bear, and #for you i guess. And what ends up happening is Dean reblogging things that Cas would like and vice versa, and it gets to the point where they’re spending more time on each other’s blogs than their own. Like, sure, Dean still reblogs stuff from all the classic car and food blogs he follows, but so does Cas and his tags are far more eloquent. Cas follows mostly nature, aesthetic, and cute animal blogs, but no post makes him smile like the first kitten gif set Dean reblogged for him: #for you i guess #why do you like them so much #they may look tiny and cute ok #but don’t let that fool you man #it’s a scam.
They have tags for Sam too, #for sam and #haha, respectively. Cas actually fills his tag with healthy recipes, exercise tips, and inspirational quotes (because he’s nice). Dean’s is just every single moose post he finds.
There’s also that one time Dean accidentally reblogged Destiel meta from Marie’s Tumblr. He didn’t even notice until Cas reblogged it and PM’d him: “I am impressed by how much she knows.” But Dean wasn’t even mad until Sam reblogged it from Cas and put #casdean #what about sastiel in the tags.
And there’s that other time Crowley joined Tumblr for a bit. He was so mad that kingofhell was already taken. He had to settle for kingofhell2.