It has been discussed in several posts whether Glitch is anti-social or not and how to make Glitch an overwhelming social experience.
Maybe it would be good to have some sort of Social Skill you can master in. How about learning something to help others? Or to learn new ways of interacting with other players?
Following that path you could learn how to double the amount of ore others get while mining (you get xp and mood in return).
There could be one skill you can only learn if you have 5 players working on it in a group. Learning that particular skill would unlock a new quest for which you need 20 more players.
Most of the things you learn would benefit others and you must interact with players instead of pigs and trees in order to move up the Social Skill ladder.
What you get out of learning those skills would be a 'warm feeling'. Which of course could be a badge, an item or the privilege to fly like an angel.
Since skills are important in the game and some of us were looking for a way to improve the social aspect it might work to put the social part in the skill tree.