OK, I was looking at the logs on my server and realized how much traffic HTML/PHP stuff actually takes up and remembered this Apache tweak that I used before, when I was adminning a couple of busy servers.
Well here it is, it has matured a bunch since I used it last.
http://www.remotecommunications.com/apache/mod_gzip/
It is quite unbelievable how much it compresses text content, I see steady 75-80% compression ratios. Plus, it makes pages load hell of a lot faster. You can notice a difference even on a fast connection like DSL or cable.
The drawbacks are
1. You need administrative (root) access to install this.
2. You need to know your way around Apache
3. It puts more load on the CPU.
but it's very worth it cause powerful boxes usually cost around months worth of heavy traffic...
It is not a good idea to compress images though, since JPEG and GIF are already compressed, it will just eat your CPU cycles.
[This message has been edited by Orgazmic (edited 11-25-2001).]