Recently, MIT Technology Review ran an article about the new uses of deep learning at Facebook. Facebook would like to use deep learning to understand more about its users. They have assembled quite a team.
If you are looking to learn more about deep learning, Andrew Ng, cofounder of Coursera, has some course materials on deep learning available on the Stanford Openclassroom site. The materials appear incomplete, but they do provide lectures covering neural networks which are the foundations of deep learning.