A new feature in the latest update to OS X Server is a caching server. This is designed to cache files in setups with multiple users so files only need to be downloaded once from the internet (or from the Mac App Store, iTunes Store, etc.). Files are cached locally, so users can save time getting downloads.
Apple has published a technical note explaining how to configure the caching server. You can set a limit to the amount of disk space used for the cache, you can choose a location for the cache, set the number of concurrent clients accessing it and much more.
This looks like a valuable feature for any organization running OS X Server.
Mac OS X Hints
http://hints.macworld.com/article.php?story=2013020523045182