classifying rear ends

[GiveMeTimeMachinePlz]

I was wondering if anybody could help me out by explaining the classification of rear ends ( Ex. Dana 60, Chevy 12 bolt, etc. ). I'm a 17 year old trying to learn as much about cars as I can, and it would be much appreciated if you guys could help me understand how they are classified and what the main differences between them are.

All help much appreciated.