It doesn't necessarily take a great developer to identify the characteristics of great developers. Does a football coach need to be a great football player?
My knowledge is about 2 years old on this but I can try to explain: TURN/STUN are to facilitate users communicating behind NAT and firewalls. TURN routes all traffic through a central server and pushes it to clients which it has an established connection with, thus getting around NAT/Firewall. STUN is a bit more lightweight in that it really just helps users to negotiate a normal P2P connection and then they send messages directly to eachother.