over 13 years ago
What is uniqe ID?
Depending on the game you are signing up for it changes
Counter strike source, your Unique ID is your steam ID. e.g. STEAM_0:0:24258937
League of Legends is similar, your Unique ID is your login name e.g. D0ll0N
It is the thing that makes you you on online games.
Gabe Newell
You are absolutely right, and I should probably have checked that before posting