If you're concerned with blocking, make sure stuff like css and important JS libs are one of the first 4 files that you serve. Also, you can just make some more subdomains for your assets. New browsers have increased the 4 files per subdomain limits too.

Interesting to see that the overhead of a secondary DNS lookup and TCP handshake can actually increase latency over just hosting the files yourself.

I started using this last week and have had a very positive experience so far.

wow looks like a great service from google again. I have been using lot of google technologies in my application lately, all of which are free.

I always wonder.. what's in it for google?

Data - they get to track what websites users visit (to some extent - limited by the "expires" header).

Knowing what web sites are popular is Google's business.

Sounds like a great bandwidth saving gift from google.