This idea has been brought up in the past, though (to my knowledge) there were never any real reasons against it. In the past there have been other lines in that section, integrity messenger for example, or later the IRC bit which was there until it stopped correctly linking to registered GTANet IRC nicks.
The idea is to add one more section, only with two fields, one for your nick/account name, another with the client/service. This would allow people to add an IRC/xfire/gtalk/etc. contact to their profile. Admittedly they could just add it to some other part of their profile, so it's not like there's a huge need, but (IMO) there's really no less of one than there was the IRC field, and I liked that, and I know quite a few people used it.
I just thought that since GTANet has it's own IRC channel/network an IRC bit would make sense. Since GTANet is a network focused on gaming xfire would make sense. At the very least those two means of communication seem to make more sense (or be more relevant anyway) than some of the existing contact sections.
Obviously if I'm the only one that thinks this is a good idea, or if it would be some unbelievable hassle (coding wise) then ignore/lock it.
Duh, this should probably be in suggestions. My bad.