For a little while now, I've been wondering why nobody has created email-like systems for social networks.<p>By email-like, I mean that it's decentralized... Everyone can run their own server. No 1 company has complete control over it. (Except possibly the root DNS servers.)<p>People can subscribe to content from others (like Twitter) and receive those updates automatically.<p>I'm thinking that when you subscribe to someone, their server is notified that you subscribed, and your server remembers it as well.<p>If the person unsubscribes, the other server is notified, etc etc.<p>When you post, your server tells every subscriber's server that you posted and gives them the message. If the person has unsubscribed, but there was no notification, an 'unsubscribe' response is returned, instead of accepting the message.<p>As far as I've thought it through, this means nobody can send you spam unless you are subscribed to them. No companies can monetize you, unless you use their server instead of running your own. With a set of standardized protocols, it should be possible to create twitter-like clients that hook to any server running this...<p>It doesn't have to be limited to 140 characters. It can have all kinds of extras, like media or hashtags built-in. Replies can be threaded, instead of hoping the other person knows why you are replying.<p>There's some other things to think about, such as what happens when a server is offline for a while. Does it poll everyone to try to catch up? Do servers send messages in batches back and forth, instead of dealing with things on a user-by-user basis? etc etc.