WP Super Cache is a static caching plugin for Word Press.
To determine if a page has been cached, view the source and the last lines on the page should read something like You’ll only see the last line if compression is enabled.
If you have compression enabled it is no longer possible to determine which cache the page was served from without looking at the page headers.
Pages served from the WP-Cache “half on” cache will have an extra header.
This method of performance enhancement does help servers handle a higher load without crashing, but is only effective when an oncoming rush of traffic can be anticipated.
WP-Cache alone, while helpful, is not adequate in many cases, so WP Super Cache was created to effectively mimic the manual page caching method, but to handle it in an automated fashion.
When a visitor who is not logged in, or who has not left a comment, visits they will be served a static HTML page out of the supercache subdirectory within the Word Press cache directory.
If you navigate to that directory you can view an exact replica of your permalink structure as well as the HTML files within the directories.
WP-Cache 2 caches the pages of your Word Press blog and delivers them without accessing the database.
Unfortunately it still means loading the PHP engine to serve the cached files. When it is installed, html files are generated and they are served without ever invoking a single line of PHP. That’s (almost) as fast it will be able to serve these cached files.
If your site is struggling to cope with the daily number of visitors, or if your site appears on Digg.com, Slashdot or any other popular site then this plugin is for you.
A classic method of preparing an under powered site for a Digg front page appearance or a Slashdotting has been to manually save copies of dynamically generated pages, and place them in directories that match the permalinks structure.