Google Page Speed can be a helpful tool for publishers and developers looking to speed their websites up. The Firefox add-on can identify bottlenecks that are keeping pages from loading as quickly as they should.
Unfortunately, some of the recommendations Page Speed makes aren't always easy to implement. So Google is trying to change that as part of its Make the Web Faster initiative.
According to Google, the performance benefits of mod_pagespeed can be significant. "We’ve seen mod_pagespeed reduce page load times by up to 50% (an average across a rough sample of sites we tried) -- in other words, essentially speeding up websites by about 2x, and sometimes even faster," Google product manager Richard Rabbat wrote on the Google Webmaster Central Blog.
mod_pagespeed requires the latest version of Apache (2.2) and Google has no plans to support earlier versions. mod_pagespeed is open source, so it's likely that it will evolve and be improved upon over time.
Unfortunately, a lot of publishers use shared hosting environments, or don't have the knowledge and resources to maximize their web server's configuration. Knowing that, Google is partnering with GoDaddy, which hosts millions of websites, and Cotendo, a CDN provider to make mod_pagespeed available to their clients.
Obviously, mod_pagespeed is an appealing tool. And it's well worth a look. But for publishers who do any sort of volume, it's worth remembering that tools like mod_pagespeed can only do so much. Maximizing a website's performance requires more than some basic web server optimizations; everything from the application to the database should be evaluated when looking for gains.