I'm very glad I installed this plugin.
Because IT TAUGHT ME TO ALWAYS DO A FULL WP BACKUP BEFORE INSTALLING (Adding) A PLUGIN.
Last night I installed W3TC (W3 Total Cache) aka W3 Total FIASCO Cache.
Today, I had to UNINSTALL it because now my site is SLOWER THAN MOLASSES in the dead of winter. It has screwed up everything. After reading up on it and googling more about it (which I should have done better to begin with), specifically "How to uninstall W3 Total Cache", I would have seen and read about other nightmares about this plugin, not to mention the hoops you have to jump through to get it out of WP and your life...
I won't repeat what has already been said and done about this poor of an excuse of a plugin, albeit that some swear by it, but others would name it W666 Total Cache instead.
In truth, it probably works great and is one of the best out there BUT... Number One, to make it so, IS THAT you either need to be a Rocket Scientist or shell out HUNDREDS of DOLLARS and the author would be HAPPY to CONFIGURE and FIX it for you.
What a Beautiful Marketing Plan he has. Bait and Switch! Bait with Free, then after it screws up your WP site, you can Switch to the PAY TO GET IT FIXED PLAN! (By the Plugin Author, of course.)
But hey, you don't have to do that, you know. You are always entitled to re-install WP and apply your Db Backups. You do have Backups, don't you? Ouch! I'm sorry. Really.