I'm using your W3 Total Cache plugin.
On Saturday, I deleted a picture and re-uploaded a new version with the same name. I don't know what happened (I'm using Smush.it plugin), but somehow the site (both administrative and production sites) went down.
Tracking down the issue, I've come to the conclusion that W3TC is causing the problem.
I know that I'm using a free plugin and that it's very difficult to have a non-buggy plugin. I just want to give you ideas, to improve it.
MAIN ISSUE: Somehow my .htaccess file, as well as my wp-config.php file were 0kb and were empty. :S
I don't know if there's a way to improve this, but in case W3TC is the one making changes to .htaccess and wp-config, I'd suggest it writes temporary copies of those files close to the new ones before making changes, so that it's easy for users to restore them.
Do you think it's W3TC the one that caused this problem? Maybe a conflict with Smush.it or other plugin?
If you need information, I can provide it on request.
W3TC version: 0.9.3