"Used by Facebook and Google" ? Citation needed. AFAIK, at least Google has an internal homebrew solution, that automatically scales to large clusters.
Google DeepMind chiefly uses Torch7. I presume parts of Twitter also use it now since they acquired Clement Farabet's startup MadBits.
Facebook's AI research lab has contributed to the Torch7 project (which is unsurprising since it is lead by Yann LeCun, and Torch7 was originally developed in his group at NYU).
I wouldn't go as far as to say it's "becoming the industry standard" though. Caffe and Theano are also very popular.
