From the wikipedia article on BDD:
BDD is a second-generation, outside-in, pull-based, multiple-stakeholder, multiple-scale, high-automation, agile me
In addition to the other answers, I have found the following links useful:
outside-in: http://www.courageousmarketing.com/pdf/outsidein.pdf
pull-based: http://www.johnhagel.com/paper_pushpull.pdf