My first day playing WoW, I met two guys that created characters the same place/time as me (undead starting zone). They were RL buds, and they just invited me to their group for the starting quests. We played together all day, and at the end of the day they invited me to their guild (now on Lothar US, was named something different then). It's been a wild ride of 4+ years but we still play together through all of our ups and downs. Most of the people who ended up being core members of HSR were different groups of RL friends that thought alike and had similar playstyles. I assume if another MMO comes out that really piques our interest, we will most likely stay a guild for that as well.