Three things:
- The chatterbox. It creates an accessible medium to talk to other members of this site. This greatly reduces the amount of faqs and questions regarding typos in code, etc. It also reduces flames by showing that it's an actual person posting that node, not just a name.
- An attractive, clean display system and the ability the modify it to suit your tastes.
- Most of all, as with all such sites, you need the management of the site to only intervene when necessary and maintain a healthy level of communication with its membership. A core group of users devoted to the site is also essential for setting an example for all users to come.
Nice job with the site :)
