So, I'm wanting to get an Android device for messing around on, but I have a few questions that I can't seem to find the answers to. What does cyanogen mod do? Is it like a proper version of Android or is there some other way of putting "pure android on an S3 etc. How do you use ROMs properly? Like, can you have more than one on the device you can switch between, for example, operating systems etc, so if I run stock JellyBean or whatever and then swap back to Touchwiz, is that possible? Are ROMs just themes or are they full OS' that replace the existing OS? Is any of this possible on Mac? All the videos I see are on Windows based computers (I know this one is probably a stupid question) and finally, if I can switch between multiple ROMs, would I have to wipe the whole device every time, or do I only do that for the initial change and can freely swap between OS'? Thanks for any help I get Also, is there any point in using cyanogen mod on a Nexus 4 if I get that instead of an S3?