Technology has made it possible to have groups whose members are not co-located, but which may still capture the benefits of traditional co-located interaction. Identification helps determine whether groups gain the benefits of co-located interaction, and how technology is used to mediate group interaction can influence identification processes. Unfortunately, in heterogeneous groups, communication technology that facilitates group identification also makes competing "fault line" identities more salient. Fortunately, channel expansion theory suggests that with effective management, groups can avoid this dilemma of media selection by learning to use lean media to communicate rich messages. When the day arrived for the three of us were to send a draft of this chapter to Terri, Greg decided that it would be funny to e-mail her a terribly underdeveloped outline, instead of the completed draft that we had finished the day earlier. Terri, seeing the outline for the joke it was, called Greg and said that it might be fun to send a message that made Mike think she had sent the terribly underdeveloped outline to the other chapter authors. Mike received the message the next day and asked Greg why he had sent an outline instead of the chapter draft to Terri. Greg mentioned his and Terri's pranks and also mentioned that Terri had copied the message to Mark-the other author on the chapter, but someone Mike had never (and at the time of this writing, still has not) met. Mike, not wanting to be left out of a good joke (but also slightly uncomfortable to pull a prank on a "stranger"), sent a follow-up message to Terri and "cc'd" Mark. The message said that Mike was so embarrassed by the outline and so frustrated with Greg, that he was going to drop his name from the paper, and was not going to present the paper at the authors' conference in New York. Mark joked back that he would be glad to present, but the title of the paper would now be "Virtual Collaboration: The Butthead Factor.".