Have you noticed improvements in speed when accessing Facebook via Google Chrome or Firefox" If you have, here?s why:
Infrastructure engineer Ben Maurer and software engineer Nathan Schloss penned a detailed blog post about how Facebook worked with Google and Firefox parent Mozilla on performance improvements, specifically in the areas of browser caches and revalidation.
Maurer and Schloss defined revalidation as when browsers repeatedly request the same content, such as logos or JavaScript code that are reused across multiple pages, and they discussed how they tweaked the browsers? expiration times and validators for that content so that unnecessary time and bandwidth was not devoted to downloading the same content over and over.
The results of Facebook?s work with Google and Mozilla were:
Both Chrome and Firefox recently launched features that make their caches significantly more efficient both for Facebook and for the entire web.
Facebook was able to reduce static resource requests made to its servers by 60 percent, giving those servers more CPU space to load the rest of the web page.
Due to examining and improving reload button behavior, Chrome in particular went from having 63 percent of requests being conditional to 24 percent of them being conditional.

The blog post went into heavy detail, and some highlights follow:
To stop unnecessary downloads, HTTP servers can specify an expiration time and a validator for each request that can indicate to a browser that...