$49 only gets you the Edison module, which is useless by itself. You also need a base board of some kind. The Edison module with the Arduino-compatible base board shown in the photos will set you back $99. Still a pretty good price. 3x more expensive than a Raspberry Pi, but it is a lot more capable.

I'd get more excited about a 64-bit ARM embedded board, but those aren't available yet, other than a $6000 development board from ARM.

Not all of the code on GitHub is open source, but the majority is -- handy, when that means an account is free as in beer, too.

I'm not privy to any details of GitHub's finances or business model, but most likely it's a good thing that there are non-open-source projects using GitHub, because that's probably what's paying for the free open source use. I've recommended to several clients developing proprietary software the use of GitHub rather than running their own in-house repositories, because the interface is easier for them to use and they don't need as much in-house expertise to manage things. Because Git is distributed, they could of course do both, or easily transition away from GitHub later, and that's a selling point.