Dan Gillmor: P2P's Promise, and Peril
"I didn't know this before today, but it turns out that a Web browser can hold open the connection to the server. Normally, a browser sends a request for information, which is delivered by the server. The connection ends.

KnowNow holds the connection open. Then it adds some JavaScript and, voila, you have a mini-server inside the browser. You're not necessarily using lots of bandwidth, but you are pretending, in effect, that you're downloading a very, very long document while the browser keeps communicating with the server."

Is that a solution to make browser-based writing safer? Server backups done on-the-fly would reduce the pain felt when your browser crashes or you close it by mistake, while typing a long post.