MMOGamer.com released first part of the GDC interview with Fallen Earth's Lead Designer, Lee Hammock, who talked extensively about the game's archetypes and their functions, in addition to describing the guild and general social interaction within the game:
Lee Hammock: For guild functionality we're actually working on developing a system where guilds can advance and level up, so if you have a bunch of people in your guild and you go through and achieve certain objectives, such as large-scale missions or things of that nature you can actually level up your guild and get guild-wide abilities for everyone in the guild. If a guild is really well-known with the merchants, you get a 5% discount when dealing with all merchants.
Or, you get a small speed bonus if you're an exploration-heavy guild. So there are basically different ways to create this social group and then do things together. A lot of missions these social groups will have to do you can only accomplish with 20 or 30 people, and they're not necessarily "Hey, go kill this one guy, you need 20 to 30 people to kill him," it'll be, "Hey, we need a hundred assault rifles." One person making them would take weeks, but if you have a whole guild, you can do it in a few days.
A lot of the crafting elements also encourage socialization, because building things like cars take weeks if you have one person to do it. If you have multiple person to do it, one guy makes the tires, one guy makes the engine, one guy makes the frame, it gets a lot more involved and you can get done a lot faster.
We're really trying to create mechanical reasons for players to work together. We have a lot of emotes, facial expressions for our characters that show emotional states, we have a lot of social spaces. Every town has a bar, and empty buildings players can go into and say, "Hey, this is going to be my place."
We have the capacity for players to rent out shops, if you go into a town you can talk to a shop rental guy, one of the buildings in town, the sign will change to show your character's name, and you can go in there and buy and sell stuff through the shop. We're trying to create all these different ways for players to interact mechanically, as opposed to just "hanging out."
Read the full interview at the MMOGamer.com