Michael was kind enough to write me and comment on my mod_gzip notes. He suggests not specifying
mod_gzip_item_exclude reqheader "User-agent: Mozilla/4.0"because it results in a
Vary: User-Agentheader which makes life hard on proxy servers and only protects the miniscule few people who run old Netscape 4.0 versions. Isn't technology fun? He also says that Apache 2.0's mod_deflate does indeed make HTTP compression easier; Apache 2 was designed for plugins to filter traffic as it is served.