I searched and searched and still I can't get the CSS and JS to GZIP encode. For example Wepagetest.org gives me this (I just put the first few lines here):
GZIP encode all appropriate text assets: 50/100
FAILED - (89.7 KB, compressed = 31.6 KB - savings of 58.0 KB) - http://www.mysite.com/wp-folder/wp-includes/js/jquery/jquery.js?ver=1.6.1
FAILED - (34.3 KB, compressed = 7.0 KB - savings of 27.3 KB) - http://www.mysite.com/wp-folder/wp-content/themes/mysite/style.css
FAILED - (15.8 KB, compressed = 5.9 KB - savings of 9.8 KB) - http://www.mysite.com/wp-folder/wp-content/plugins/fancybox-for-wordpress/fancybox/jquery.fancybox.js?ver=1.3.4
FAILED - (9.9 KB, compressed = 2.2 KB - savings of 7.7 KB) - http://www.mysite.com/wp-folder/wp-content/plugins/fancybox-for-wordpress/fancybox/fancybox.css?ver=3.2.1
FAILED - (9.3 KB, compressed = 4.2 KB - savings of 5.0 KB) - http://piwik.mysite.com/piwik.js
FAILED - (6.0 KB, compressed = 1.5 KB - savings of 4.5 KB) - http://www.mysite.com/wp-folder/wp-content/plugins/sociable/css/sociable.css?ver=3.2.1
This has been brought up many times, without being answered. The author did reply a few times with arrogance saying it works fine. Some suggestions are to make sure minify is on, and to use help on the minify page.
Well thank you for that, IT IS ENABLED ALREADY. I disabled all gzip options, saved, cleared cache, re-enabled them, cleared, rinsed and repeated countless times, compression never kicks in.
YES - Gzip compression is installed on my server. That, and all other modules required are installed.
Also nowhere can you find an option to "combine" or not the CSS and JS. Some options to "combine only" or "combine only" before body or head, etc. Where's the option to combine? No way to say if it's on.
Then I saw another suggestions somewhere else: To uninstall, delete and reinstall. So I proceeded to do that.
THIS PLUGIN DOESN'T UNISTALL???
I deactivated and deleted. Tested the site with webpagetest.org and Google Page Speed. Have the same speed as without W3 Total Cache. Strange, right? So I reinstall W3TC, and all my settings were the same as before. Settings were not removed on delete. Maybe even caching. So I reset settings.... All the manually entered JS and CSS in minify were still there.
IMAGE CACHING and EXPIRE date.
Just another quick thing. I searched and searched. This plugin doesn't set expiry headers correctly. Many images won't be cached. And from what I read, images that were created long before you installed this plugin won't be cached because W3TC sets the expiry relative to the image creation date, not access time. Author said option to chose the expiry method would be implemented. So someone asked a year ago"is it updated by any chance?". Author replied "Yes". Well it's not. If it is, then I didn't find it. Try to find anything in this spaghetti interface. Total mess.
Another thing the so nicely designed documentation for this plugin doesn't tell you is which folders WT3C will set the image expire date for.... Will only work for images in the folders where you upload images in WP (not images uploaded to another folder manually).
This plugin might increase your site performance, but it's a mess and only basic functions will work properly for most people. The author will tell you "well, try without W3TC, and without, see, it works". Yeah that's because the most basic caching function, to make static pages, works. That's what makes the biggest different and any other cache plugin will do just as well or better. Sure W3TC offers lots of functions. But they don't work really well and confuses non-tech people.