Warming the cache gives your users extremely fast pages all the time. Using varnish, xmlsitemap, cron and bash you can give your clients very fast pages.
Getting to understand the Varnish caching rules.
http://benbuckman.net/tech/11/12/making-sense-varnish-caching-rules?utm_...
Using Varnish & Pressflow to Make Managing News Faster. http://developmentseed.org/blog/2010/jan/04/using-varnish-pressflow-make...
Pressflow, Varnisch and caching. http://blogs.osuosl.org/gchaix/2009/10/12/pressflow-varnish-and-caching/
