Be aware that MSIE (5.5 SP1/2 and 6 without SP) corrupts cached compressed pages. A fresh install of XP (IE6), for example, shows corrupted pages the
second time that you access to some site that gzip pages and allow caching of these (sending Last-Modified headers, etc.).
See some of the MS articles about this:
Q313712 and
Q312496.
Sadly, thanks to this widespread bug, we should choice between compress pages, or allow caching.
Slashdot and Google doesn't allow caching, I think.
José