when end user accessing this site it has to travel through wire from few hundred miles to thousand miles.for avoiding these microsoft come up with new network called "Content Delivery Network".
if we use this in our project the performance will increase.
let me explain how it will increase the performance. suppose if you are accessing the site in India.
Content delivery network will find the shortest distance network and then it will load the all library files.
Instead of loading from one place.
Example:
<script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.3.2.min.js" type="text/javascript"></script>
instead of mentioning our own path
