A browser-based IM client from AOL. You heard it here first folks.
Link archive: July 25th, 2007
Great article from Brian ranging from introducing microformats right up to the current state of play.
The justification behind YSlow. If you've heard Nate Koechley speak, some of this will be familiar to you. It's all solid advice as far as I can tell.
The YUI folks have released an add-on for Firebug that will analyse your pages and suggest ways of speeding it up.