Linux-based btw! But 100$ still is an unthinkable lot of money for people below poverty level. And what about the language? Linux is great, but it doesn't support every language on earth. I thinkt the most important point is not hardware but education. If you don't speak one of the most common languages you can't tab into online knowledge databases, even if the blurry connectivity vision of MIT works on day the notebook is a good idea, but what about teachers to teach how to use it?

MIT FAQ:
What about connectivity? Aren't telecommunications services expensive in the developing world?
When these machines pop out of the box, they will make a mesh network of their own, peer-to-peer. This is something initially developed at MIT and the Media Lab. We are also exploring ways to connect them to the backbone of the Internet at very low cost.