The Nicknames

I'm not exactly sure on what the nicknames do. I saw J-Dog introduce himself as Justin to the girl on S1E1 of The PUA. If it's just to address each other in the community, do i really need one?  I mean don´t get me wrong it sounds like fun (I was thinking maybe Doc or Psych) but I don't know PUAs in person and EddieJoe is just my name in english, Eduardo Joel.In The Game this is never expressively convered, only glossed over.Do you guys have nicknames and what purpose do they serve for you?