For folks interested in his #2 benefit (using multiple domains causes static assets to be loaded in parallel, speeding up observed speeding page load times) -- you can capture it without involving Google in the slightest. It requires a perhaps two-line tweak to your web server configuration files to make it answer requests on domains other than www.example.com
For example, my main domain is www.bingocardcreator.com . There are some honking images which load on the front page that used to block the (more valuable to my conversion pathway) images on the sidebar from popping up. I reconfigured my webserver to accept images1 through images4 as acceptable host names, and (lazily) manually split the static assets over the 5 hosts.
This actually resulted in improving the loading of my sidebar by upwards of a second. That is worth, oh, probably $100 a month or so. (If you do not know how I can possibly say this, you owe it to yourself to try CrazyEgg right now.)
Not bad for an hour's work that never has to get repeated.
Credit given where credit is due: I found this tip out through using Yahoo's YSlow plugin for Firefox, and following their "Best Practices for Speeding Up Your Website". This document is one of the best practical "Here, do this, it will make you money" sources I have ever found on the Internet.
This is a tip that I've also used to great effect, but I thought that I should point out (if it isn't obvious) that you must make sure the same image always points to the same subdomain (image 1 is always linked to images1.mysite.com) otherwise you'll shoot yourself in the foot by eliminating browser caching.
I usually write a quick function in $language to turn the first few letters of the filename into ASCII then modulus by the number of fake subdomains that I've set up to decide which server to link to. The overall distribution may be imperfect but file x will always be linked to server x across pages, so it's a nice quick solution, especially if you have multiple maintainers.
For example, my main domain is www.bingocardcreator.com . There are some honking images which load on the front page that used to block the (more valuable to my conversion pathway) images on the sidebar from popping up. I reconfigured my webserver to accept images1 through images4 as acceptable host names, and (lazily) manually split the static assets over the 5 hosts.
This actually resulted in improving the loading of my sidebar by upwards of a second. That is worth, oh, probably $100 a month or so. (If you do not know how I can possibly say this, you owe it to yourself to try CrazyEgg right now.)
Not bad for an hour's work that never has to get repeated.
Credit given where credit is due: I found this tip out through using Yahoo's YSlow plugin for Firefox, and following their "Best Practices for Speeding Up Your Website". This document is one of the best practical "Here, do this, it will make you money" sources I have ever found on the Internet.
http://developer.yahoo.com/performance/rules.html