The idea behind "CacheFile.net" is that you could provide a common source for javascript libraries and images to be served from . I have actually pondered this idea before, but there is one huge issue that pops up everytime, security. You're including a remote javascript file on your own website, which could be "altered" to do malicious things via a cross site scripting attack to grab users cookies, redirect them to phishing sites, and all of the other nasties that come along with it.

Since there is a common source, hackers could concentrate their efforts and infiltrate every single site using the service at once. Not to mention it creates a fairly large single point of failure if the cache were to go down at anytime.

There really would need to be some way of "authenticating" the file each time you include it, and well, every solution I can think of either totally negates any speed gains made by the common cache.

One last point, is that this site seems to not work on https pages, which is a fairly major point, as browsers will throw up all kinds of errors if you try and include non-secure files on an secure page (and rightly so).

In short, it's a really good idea in concept, but the risks are simply too great for it to be of any use in a real world environment.