What I would love is federated social networking somewhat like e-mail works on various servers transparently)
Even the federated model of e-mail has declined over time, with the vast majority of people using an e-mail address from a handful of large providers like GMail. Universities and companies are under pressure to have all the e-mail under their domain names actually served through GMail instead of running their own infrastructure. If you want to run your own server, there are a lot more hoops to jump through these days before you can federate, otherwise things you sent out just end up in spam folders. (These hoops are generally reasonable anti-spam ones, but they are nonetheless very different than a decade or two ago.) And now certain websites that monetize the hell out of their userbase are refusing registrations if the e-mail address you enter is from a domain that doesn't nudge its users into adopting a format like firstname.lastname@example.org.