Limited resources ? Slow servers ? WP-Cache will let you survive a digg! WP-Cache is an extremely efficient WordPress page caching system to make your site much faster and responsive. It works by caching Worpress pages and storing them in a static file for serving future requests directly from the file rather than loading and compiling the whole code and then building the page from the database.
WP-Cache allows to serve hundred of times more pages per second, and to reduce the response time from several tenths of seconds to less than a millisecond.
PS : Please turn GZIP compression OFF (if enabled) from Options->Reading.
Server load with and without Cache enabled
Source : WP-Cache 2
Wp-cache is an excellent plugin. I’ve been using it on my blog for 8 months now.