For years people have tried to figure out how Google manages to produce lightning fast search results from the huge amount of data that they have to work with. They are still not giving away all of their secrets, but they have a released a free tool and a set of web site develoment "best practices" to help web site owners improve the performance of their web sites.
The new Google tool is called Page Speed. Page Speed was introduced in Google’s Webmaster Central Blog. Page Speed is a free downloadable tool that works in conjunction with the FireFox browser (sorry, no IE version) and the free FireFox Add-On called Firebug. You must have a current version of FireFox and Firebug installed before you can use Page Speed. The tool can be downloaded from the Page Speed web site.
The second part to this tool is the release of a series of documents detailing Web Performance Best Practices. This is a pretty comprehensive group of instructions for improving web site performance through reduction of server requests, consolidation of external files, proper use of images and other coding and server configuration techniques.
The documents offer logic that explains the importance of loading external JavaScript CSS files in a particular order, as well as when they should be split in to multiple files and when they should be consolidated to improve performance. I found the section regarding CSS best practices to be the most interesting. We have not yet implemented the CSS techniques, but plan to test them. It is interesting that many of the CSS coding methods commonly used in WordPress themes and other open source software is specifically addressed as being very inefficient and therefore not recommended.
The best practices documents can be challenging to understand, unless you are an experienced code monkey. Nonetheless, they should be read by anyone who works with HTML, JavaScript and CSS. if you pick up one new technique that improves the performance of your web site, the time was well spent.