So instead of making one huge friends page request and getting back a rendered document with 95% duplicate stuff that your client has already downloaded 15 seconds ago when you habitually hammered refresh, your client instead makes dozens of tiny requests, easily cachable on both the client and server, all the way up to the BIG-IP where I can later just instruct it to 304 any If-Modified-Since request on certain immutable URLs. (ala /userpic/ requests)
Anyway, works in IE/Safari/Firefox. Been reading my friend's page in it the past couple days. Pretty addictive.
I'll post a URL when it's beautified a bit and it's not lacking 75% of its future feature set.