The most exciting move in Acquia for me so far just happened a few days ago. We rolled out what was called "Big tent" internally, and means much wider support for all Drupal 6 sites. As Dries points out in his blog post, we used to support our Acquia Drupal distribution via forums, tickets and phone support. However, we found that virtually all sites will use other modules, custom code and themes, tweaks to existing code.
Drupal related posts by Gábor Hojtsy.