Virtual communities are often bound by a platform: some sort of place where the community is represented. This is not to say that every platform is a community, or that every virtual community must be represented in specific place. But technologies like message boards, vlogs, blogs, media sharing sites, social book marking sites, and traditional social networks (to some degree) often serve as a representation of the community, both as a proxy for geographical proximity and as a display of community actions and affiliations.
These representations of community are often presented as lists: what happened recently, who recently acted, what is popular, who is worth paying attention to, and what place the community holds in the world (press, lawsuits, taunts). These lists give members of the community a shared history and culture, they create heroes and villains, and they help members to place themselves within the overall structure of the community.**
In order for these representations to work effectively, community members need to have some understanding (true or not) as to how the representation is created: what sort of mirror is being used to reflect the community back to them. There are two main models of understanding. One is that the representation is created by an algorithm, and the other is that the representation is created by a central persona or central personae. These models are at two extremes of a continuum.
Algorithm, in this sense, is a set of rational, non-emotional rules that is seen to determine the mirroring of the community (most diggs, newest, word filters, page rank).
On the other hand, a community might imagine that a central persona is doing the mirroring. A central persona is imagined as a human mind that is both rational and irrational. It thinks and feels. It can be angry, unjust, jealous, or benevolent. It can make mistakes and it can apologize. It can represent the community by selecting what is cool, what is lame, what is weird, what is hopeful and what is touching.
These models are at two sides of a continuum; most often the representation of a community is seen as a mixture of the two.