[kevinp]

Mind if I answer this?

Android is a free operating system mostly developed by Google. It has to be modified slightly to run on certain hardware. B&N has modified the version for the Nook so that you can pretty much only access their stuff. Picture running Windows on your computer, but only being able to look at Internet Explorer and run no other programs.

CM7 has been modified by some talented programmers to run on the Nook and open up the operating system to allow you to run whatever you want. For example, the Google Marketplace is now accessible, so you can download and install apps from it.

The only downside is that the fluff B&N puts into the Nook is not accessible while you're running CM7. But you can download the Nook app from the Google Marketplace (now called "Google Play") to read your Nook books and magazines. You can also install the Kindle app if you have any Amazon ebooks.

The good news is that you can run CM7 directly from an SD card without actually changing anything on your Nook. All you have to do is restart your Nook to put it back to the original operating system. Restart it again to switch back to CM7.