How much is too much?
But yes, I think "too much" is well.. too much. People might say they have all the friends they need in PE. -Internet friends cant provide you proper comfort however.. they cant be there when you dont want to be alone, no matter if you and them are online or not. People need human contact, to see people, facial expresssions, socializing. Yea, its much easier talking about things over net, but its also good to have a friend irl that can only look at you, and without you having to say anything -know you are having a bad day.
Its not unusual that people spending "too much" time in front of comp develops agorafobia and social angst.
People thinking that "they cant party, they have a society meeting/event/hunt/write excuse here" every time they are invited somewhere, or doesnt socialize because of the game is holding them back should take it as a warningsign.. If they dont do anything about it, people will stop inviting and suddenly you snap out of it, get tired of PE or such and realize you have to skill yourself up again irl and make a social network all over.
IRL should come first.