Varnish Cache has a large community of users that we know love its flexibility and ability to empower.
Once upon a time DDoS attacks where something rare. Now, not a week goes by without such an attack on a customer or a prospect.
In connection with the Velocity conference we're doing our two day Varnish Administration Course in San Francisco.
If you have a really big web farm you'll have lots of backends and some sort of complex mapping between virtual hosts and web servers.
My favorite Varnish branch these days is the persistence branch.
Since the release of Varnish 3.0 last summer there have been quite a few minor performance enhancements in the development branch of Varnish.