What are the primary differences between TDD and BDD?

Test Driven Development has been the rage in the .NET community for the last few years. Recently, I have heard grumblings in the ALT.NET community about BDD. What is it? What makes it different from TDD?

Behaviour Driven Development seems to focus more on the interaction and communication between Developers and also between Developers and testers.

The Wikipedia Article has an explanation:

Behavior-driven development

Not practicing BDD myself though.

It seems to me that BDD is a broader scope. It almost implies TDD is used, that BDD is the encompasing methodology that gathers the information and requirements for using, amongh other things, TDD practices to ensure rapid feedback.