This is something that's always baffled me, for some reason it has only just occurred to me to post on the subject. To wit; we have a "friends list" to which you may add players with whom you wish to develop and maintain relations, yet this list neither performs nor enables any function with regards to actually developing or maintaining said relationships... Ok, so i've ignored the function of being able to see which servers your friends currently hold accounts on, but that function is so limited it barely seems worth mentioning. Sure, you can sign up to one of the servers hosting some of your friends, you may even be fortunate enough to find some of them in the same quadrant as you, but that's all.
I like the idea behind the friends list, but i think it's rather under-exploited. There are a lot of things that could be done with it, but starting with an out-of-game messaging system seems logical and possibly most simple to implement (he says, with absolutely no knowledge of the work involved...). In future perhaps we could see in-game tagging, or the ability to locate friends' positions on the map before joining a server, or even limited group spawns.
No doubt there are endless pros and cons i haven't considered to the various suggestions made here, but i think it could be a game-changer for the general community. While i hesitate to validate any complaints about pre-made teams being too powerful, the ability for new or unaffiliated players to utilise their friends list to a greater degree would go a long way towards balancing the scales in-game. More than that, i think widening the scope for communication and collaboration would encourage more new players to stay with the game, especially where this game is quite so dependant on good team-work.