Just from a quick check of http://en.wikipedia.org/skins-1.5/monobook/main.css?55, removing all the possible white space will reduce it in size from 30882 bytes to 23411 bytes, saving 7471 bytes (24%). That's a drastic change in size, and if done would save a ton of bandwidth (over time).
It's small compared to actual compression, though.
Exactly. To quantify with mod_deflate :
------------------------------------ root@bling:/var/www/hosts/mediawiki/wiki# curl --silent --include --head http://192.168.0.64/wiki/skins/monobook/main.css?55 HTTP/1.1 200 OK Date: Thu, 08 Feb 2007 01:20:04 GMT Server: Apache Last-Modified: Mon, 05 Feb 2007 23:57:09 GMT ETag: "709d-428c37389ff40" Accept-Ranges: bytes Content-Length: 28829 Vary: Accept-Encoding,User-Agent Cache-Control: max-age=2592000, public Content-Type: text/css
root@bling:/var/www/hosts/mediawiki/wiki# curl --silent --include --head --header "Accept-Encoding: gzip,deflate" http://192.168.0.64/wiki/skins/monobook/main.css?55 HTTP/1.1 200 OK Date: Thu, 08 Feb 2007 01:20:12 GMT Server: Apache Last-Modified: Mon, 05 Feb 2007 23:57:09 GMT ETag: "709d-428c37389ff40" Accept-Ranges: bytes Vary: Accept-Encoding,User-Agent Content-Encoding: gzip Cache-Control: max-age=2592000, public Content-Length: 7763 Content-Type: text/css
root@bling:/var/www/hosts/mediawiki/wiki# ------------------------------------
I.e. 28829 bytes reduced to 7763 bytes saves 21066 bytes, which means a saving of 73%.
And you don't have shadow versions of files, and the version that gets sent to clients is still legible (and it's the same one that developers know and are familiar with).
[P.s. please ignore the "public" directive in the cache-control line above, it's not there by default, I've just manually overridden it to test stuff. ]
All the best, Nick.