Last week, I saw a great post on Hacker News showing off a simple plain text twitter clone. The idea was that you pointed your client at plain text files hosted by your friends. To write a new post, you append a new line to the file on your webserver. To read your friends' posts, you get all their URLs and look for new lines. While it was simple and easy to implement for people hosting their own servers,
it would be a hassle for many people, myself included, to set up.