Interesting idea. However, as far as I can tell, this will not work well from a security perspective; 1) No support for https (and implementing anything would be non-trivial -- either all clients would need a certificate trusted by all others (eg: cacert client certificates) -- as mixing signed and unsigned data on a page is unsafe, this would "break" ssl-enabled pages) and 2) No protection against rouge clients sending different data (from spoofing to exploits targeting image handling libraries).