Check out this slideshow by Robert Douglass at a recent conference in Europe. Pretty heavy on the Acquia love, but a nice overview of some ways large companies are rolling out dozens of sites and micro-sites to as many different audiences with Drupal.

This was actually a large part of my daily responsibilities while working for Popular Science. We spent a lot of time working on a site for the annual Best of What's New promotion (the email for this year's BoWN just went out), as well as some micro-sites for a sports promotion, and the B2B part of BoWN.

Drupal's multi-site capabilites, combined with things like Themes, Internationalization, Installation Profiles (or Features), and finally management products like Aegir, can really make rolling out a few dozen Drupal sites just as easy as rolling out just one site. We've actually had talks about this at some recent Florida Drupal User Group meetings.