An interesting article by Steve Herbert about Code-Talking. This is the name he gives to the process whereby developers feel free to share code, ideas etc for the benefit of the team as a whole. Steve talks about how this skill can't be mandated by management, and points to the environment being created by Developers.
Code-talking is usually a passion held by two or more developers on the team. The talking becomes contagious between team members and the desire to contribute a new approach or pattern to the group’s idea toolset becomes a running desire among the developers.
Personally, I've found this tough to sustain at a team level unless everyone is working on similar projects. One of the things I want to do is to implement a method to record these conversations (either email or blogs as Steve suggests) so that everyone on the team can benefit.