That's not the issue for hosts.  Depending on how the host is running, using compression on a site/folder can cause some dramatic memory increases, even causing some other sites to stop responding.  It's not really an IIS issue as much as a host trying to do too much with too few resources, but that's what happens with cheap hosting.  IIS7 has corrected a lot of these types of issues for hosters.

Although you're correct, Port80's solution is a lot better than basic compression from IIS.  Compression also got a lot better in IIS7.  And I really haven't seen any issues with having both IIS and DNN compression enabled, though I'm not convinced I'm getting a real benefit (Testing doesn't show a marked improvement for me anyway...).

Jeff

I'm wondering if it's possible to test to see if IIS compression is switched on or not via an ASP.NET script calling IIS?

Anyone know if this is possible/got code on how to do it?
It would be great enhancement for the new DNN dashboard for instance (in fact I already logged it as a suggestion).
http://support.dotnetnuke.com/issue/ViewIssue.aspx?id=9048&PROJID=2

I modify IIS settings using ADSI and I am sure every IIS setting is configurable programmatically. You can also use WMI or a script.

http://blogs.technet.com/wbaer/archive/2008/01/30/http-compression-internet-information-services-6-0-and-sharepoint-products-and-technologies.aspx