Page compression is a way for your browser to download a smaller version of the pages here so that it loads faster. As you might know from saving a large document of words into a .ZIP file, it can compress a very large file into a very small size. Same thing works with the Internet. When your browser tells the server it can accept compressed content, the server sends content compressed by GZIP. This can make a very large page compress by anywhere from 50-90%.

When your browser isn't accepting compressed content, it takes longer to download the page, and uses more data transfer (bandwidth). All modern browsers support getting compressed content, but some things may filter out the browser's notification to the server that it can accept compressed content. Ad Muncher, for instance, removes the browser's notification that it can accept compressed content. Because of the way Ad Muncher's filtering works, it can't deal with compressed content. So, having Ad Muncher running on your computer can cause the compression warning to appear. In this particular case, you will need to exit Ad Muncher entirely in order to get it to stop filtering your browser's connections.

Other things that may prevent the ability to compress content are web proxies that don't support it, or older browsers where it wasn't implemented yet.

The primary things that this would slow down are rapidly loading several pages one after the other, or using the in-game recruiter (which basically does that in the background for you). For the best in-game recruiter experience, we recommend the Safari web browser for all Windows or Mac users, as it is currently the fastest Javascript processor of all modern browsers we've tested, and the game relies heavily on fast Javascript processing in order for the in-game recruiter to work smoothly.