Drupal is an Open Source content management system currently used to power more than 1% of ALL websites. It ideally runs on PHP, MySQL and Apache. For more info, check http://www.drupal.org/
Varnish is being used a lot on large sites to optimize performance. It is a very fast HTTP cache server, which is to your Drupal what a big rotation press is to a newspapers DTP system. Want to deliver thousands of pages per second with very low responsetime ? Varnish is your tool for that. And Facebooks, and BBCs, and SlashDots, and...
After two days of hacking core (aka code sprinting) DrupalCon is finally starting today. I planned a lot of sessions to attend (one every hour) and I'll try to live-blog every presentation. My first presentation of DrupalCon is the one given by Jeff Miccolis of Development Seed and Irakli Nadareishvili of Phase2 Technology about Drupal Distributions.
One says doing thing you love makes it easy doing them. Who thinks cooking is a burden, if nothing makes you happier than buying fresh fish, herbs and pasta and spend the rest of the day in the kitchen preparing your loved ones a mouth-watering diner? Who hates a broken car if you have the best weekend by fixing the brakes while cleaning the engine as well? And who could become tired of walking if that's the thing you love most? You got my point.