That’s a very good point. One line of thinking I’m interested in is social networking over email.

Everyone has email, so you could imagine a social networking app that’s just a thin layer over your email, and every interaction is encoded as an email being sent under the hood. Want to share a picture with your friends? Send an email. Someone wants to comment on it? They just send an email. Etc.

The main purpose of the app would be to offer a nice, device responsive, consistent presentation. Additionally if this were an open, documented standard, an entire ecosystem of “email apps” could emerge.

(Of course as far as your actual email account goes you’d want to auto archive the emails + not get notifications for them, but that’s easily configurable)

We could do all the same things on the web, so long as the standards are open. But that's exactly the problem - lock-in is how social networks make profits, so the largest ones (where most people already are) are also the least likely to support anything like this.