mod_deflate or mod_gzip, which should be used?
I read mod_gzip on better explained but want to know extra about mod_deflate.
You should read "Compressing Web Content with mod_gzip and mod_deflate" by Stephen Pierzchala.
From a pragmatic point of view, I suggest mod_deflate because it is easy to configure, well documented, and actively maintained. Also, a precompiled version of mod_deflate is more than likely available for your server. Apache may even come with mod_deflate, as is the case with the Windows installer and apache2.2-bin Debian package.