Google Code blog has recently optimized their blog for performance improvement. The team used a lot of the principles from Steve Souders book: High Performance Web Sites, "only 10-20% of the end user response time is spent downloading the HTML document. The other 80-90% is spent downloading all the components in the page (p.5)", and ended up with a nice gain:

According to our latency measurement stats, the user-perceived latency on Google Code dropped quite a bit, anywhere between 30% and 70% depending on the page. This is a huge return for relatively small investments we’ve made along the way, and we hope you’ll find these techniques useful for your own web development as well.

The changes were low hanging fruit that most of the sites could also implement:

• Combined and minimized JavaScript and CSS files used throughout the site
• Implemented CSS sprites for frequently-used images
• Implemented lazy loading of Google AJAX APIs loader module (google.load)

Google Code, Blog, Website, Optimization, Performance