As far as I can tell, quite a few ML people can vouch for someone at the company (I know someone there second-hand myself), but the details of what precisely they're doing have been kept fairly well under wraps. The broad parameters are "something to do with Artificial General Intelligence (AGI)", which is a field that tries to straddle the fine line between contemporary AI and sci-fi AI, without erring too far in the direction of either too incrementalist to too pie-in-the-sky. More specifically on the "methods" side, they have people who are known in both statistical ML, and in the recent resurgence of neural-networks known as "deep learning".
You can discern some more about their general direction by looking at courses they've been involved with, talks they've given or sponsored, etc., but as far as I know (and I tried to probe a few months ago through a friend who knew someone there) their actual product / business / etc. hasn't really been leaked, or at least not leaked widely enough that I could find out about it.