Not too long ago I was working on a web app at my place of employment with several other people. It's a fairly complex app that makes heavy use (too much, IMO, but that's a different story) of AJAX. When we finally made this application available for beta testing our IT department was quick to point out that each request was causing over 1MB of bandwidth usage. After my initial shock my first impression was that the problem was being caused by the set of 3rd party tools we were using. However, a simple test using a page with intrinsic framework controls revealed that my suspicions were incorrect. It took many hours of frustration but eventually I noticed that debug in web.config was set to 'true'. Once I set it to false our bandwidth usage dropped to a very reasonable amount in the range of 12k to 75k, depending on the data being served. So, use my experience as a lesson and don't ever forget to set debug="false" before deploying.