Last fall or winter I convened a few "Shop Talk" conference calls to bring Drupal development shops together on the phone to talk about projects, modules and other things related to the work we do with Drupal.
The idea stemed from my discussions with Phillip Smith, Mike Gifford and Joe Murray at
Web Of Change in 2005. Since then those discussions have morphed into what I call "The Three 'C's": Communication, Cooperation, Collaboration.
There is a continuum of interaction that starts with communication and hopefully ends in collaboration. But you have to start talking first. This is why DrupalCon, Drupal User Groups, Drupal Groups and the Drupal Shop Talk are all important. They bring together people who are, despite the opensource nature of the Drupal Project, often isolated so that they can learn what eachother are doing, and avoid duplication of work (for starters) and collaborate on bigger and better things.