The time it takes for your page to load has been a ranking signal for quite some time. In the past, Google has released tools to help you determine how fast (or slow) your page loads, including Site Speed Report in Analytics, Page Speed plug-in for Chrome, and Page Speed Labs (complete with API) to help optimize your site's speed.
Apparently these tools aren't enough. To "simplify the life of webmasters," Google has launched another service to help increase page speed. Simply called Page Speed Service, the new tool is an actual online service that essentially supersedes your Web server.
Page Speed Service fetches your content from your Web server and caches it on Google's servers. The service requires you to point your site's DNS to Google.
In essence, visitors to your website actually go to Google's servers instead. Because the servers are mirrored around the world, network traffic is no longer as much of an issue. While your site will still load quickly, it will be loading from Google's servers.
With their other services, Google offered reports and action items to improve your site's speed. In some cases, they went so far as to automatically rewrite your Web pages to optimize them for speed.
Google's offer is tricked out hosting, not a page optimizer. You have to set your DNS to point to Google instead of your current Web host. This means when someone types in your website, Google's servers will answer, not yours.
Yet, this appears to be an automatic caching service. You'll still need your current Web hosting provider so you can make updates to your site, which Google will crawl, cache, and propagate to their servers worldwide.
Google's current plans are to offer Page Speed Service to a limited set of webmasters free of charge - for now. Pricing options will be announced "later," but Google promises it will be "competitive."