"Beware of geeks bearing gifts"!
As the story points out, had the MIT project accepted the donation of free copies of OS X for the $100 PC project it may well have become the dominant operating system in the developing world. That happens, and all of a sudden, poor people with much, much better things to do with the little money they have than pay for proprietary software are locked in. Instead, the project will use Red Hat Linux and associated free software. (That's both free as in beer and free as in freedom.)
This project will almost certainly come to fruition. It has too many backers with clout to fail. In my less than humble opinion, this is one of the most exciting projects extant. Every one of these PCs will bring another person or three into contact with the wider world, with all the potential that implies for spreading knowledge, enhancing lives and breaking down intolerance.