make sure you are testing this as an anonymous (logged out) user, since the rendering is significantly different in that case, and anon users account for 90%+ of our traffic.
Also, what Cletus said:
- ETags are worthless
- Content delivery networks are worthless for anyone except Google and Yahoo scale websites
- We don't control a lot of the things YSlow is complaining about (eg, Gravatar images, references to Google Analytics .js and Quantcast .js, etc)
In short, Yahoo's Problems Are Not Our Problems
That said we did register sstatic.net and we do plan to serve up images and stuff from a cookieless domain at some point. That's about the only rational optimization left.
This is done.