Clearly, some things do not foster community. You do not need a real identity, but you need some identity. You need to have a voice, a reputation, a presence to be part of a community, because it is (at least) a two-way propositions. Thus "lurkers," people who only read or listen, are not really part of a community. They may fancy themselves to be, but no one would miss them if they left. They are fans, not friends. Lurkers may latch on to a culture, but they do not contribute to it. (That's why fandom is so eerie: There's usually no real communication between the fans and the stars, just lurkers and fantasies on one side and a PR machine on the other.)

Lurkers are fans, they are not participants; however, they could become participants if the system encourages it, like how Slashdot does with their comment rating system.

Asymmetric attention is the key to another important concept, celebrity. Being famous means that a lot of people pay attention to you--after all, by definition it is famous people who appear on the cover of magazines, which are purchased because lots of people want to know what\'s happening with their favorite celebrities. But the celebrity doesn\'t, for the the most part, pay any attention to the fans (at least, not individually). Asymmetric attention ties in Twitter allows people like Oprah Winfrey to have millions of fans, just like she does on television, without needing to pay attention to all or even any of them. In short, asymmetric attention allows Twitter to be an extension of other forms of mass media as well as a conversational medium.

Likewise, the existence of symmetry is informative as well. If two people follow each other, then they are each paying attention to one another, and each is receiving information from the other. This is powerful stuff, even more so if each has sent @replies to the other, because this is better evidence of a strong social tie between them. Note that the exchange of @replies makes a symmetric connection out of two asymmetric ties.

Twitter provides for asymmetric connections, where individuals follow others, making the people who don\'t follow back are celebrities; however, the system has been hacked with @replies, which make asymmetric connections symmetrical.