Just wanted to pass this along for those of you that might be affected. I host several WP installations on Webfaction.com. I recently discovered that WP Supercache was not serving the cached versions of pages.
* Supercache plugin reported "0 cached pages", yet files were being created in the wp-content/cache dir.
* meta directory was empty
* supercache sub-directories were being created, but the index.html in each was not
* when viewing page source, I could see the comment about the build time of the dynamic page, but not the comment letting me know that Supercache was serving the cached version
I spent some time fussing with permissions and checking .htaccess contents. Finally, at Webfaction's recommendation, I created a new instance of WP and moved content over bit-by-bit, checking along the way. When I added the Kimli plugin, proper caching stopped. Disabling the plugin caused caching to resume.