I have compression enabled within IIS7 and it works as expected on all responses except for those constructed by ASP.NET AJAX. I have a web service that provides data to the cl
In general you don't want to do this unless you wouldn't mind throwing orders of magnitudes the amount of server power into your apps...
Also not only server-CPU but also client-CPU becomes a problem when you do this....
This concludes with that your app becomes WAY slower if you GZip all your Ajax Responses...!