In a rather interesting turn, Google are now serving popular JS libraries from the speedy servers that make up their Content Delivery Network.
These are available for all to use, the theory being that an end user may already have a cached version of the library already on their machine from a visit they made to another website, thus speeding up the loading time of your own site. If the user does not already have the library, it should download at a fairly blazing speed to their machine.
For us to use this creates a dependency on Google continuing to maintain this service. That said, we don’t really blink twice before adding Google Maps to our sites, so why should this be any different?
http://code.google.com/apis/ajaxlibs/documentation/index.html
The scripts can be called directly or via Google’s AJAX API.
E.g. Load MooTools compressed directly: http://ajax.googleapis.com/ajax/libs/mootools/1.11/mootools-yui-compressed.js
Load MooTools via Google AJAX API: google.load("mootools", "1.11");