The tldr is that Balaji and 21e6 have done nothing more interesting than use millions of dollars of opm to build a huge mining pool out of custom silicon that performs so well the 70M it took to build it just makes financial sense on its own, netting in the low eight figures currently.
Now the followup strategy is to give away free mining chips for embedded systems to 1) mine more coins using other people's power (21 keeps 75%) and 2) stabilize the long the term value of their massive BT holdings by promoting consumer adoption of bitcoin (by bribing people with free coins mined by their own gadgets)
