It’s clear that Varnish and high-traffic portals like Twitter and Facebook go hand in hand. A write up on highscalability.com notes that Tumblr is using 15 Varnish servers as part of its server fleet. Besides proxying, they’re being used to serve up public blogs.

rc7 is out! We’ve upgraded to Varnish 3.0.2, fixed some bugs, and made some improvements to make your server run even faster!. Head out to the varnish download page: http://www.unixy.net/varnish