And I doubt it's unique to LessWrong

Relevant link: The Tyranny of Structurelessness (which is mostly talking about real-life political groups, but still, much of it is relevant):

Contrary to what we would like to believe, there is no such thing as a structureless group. Any group of people of whatever nature that comes together for any length of time for any purpose will inevitably structure itself in some fashion [...]

Elites are nothing more, and nothing less, than groups of friends who also happen to participate in the same political activities. They would probably maintain their friendship whether or not they were involved in political activities; they would probably be involved in political activities whether or not they maintained their friendships. It is the coincidence of these two phenomena which creates elites in any group and makes them so difficult to break.

These friendship groups function as networks of communication outside any regular channels for such communication that may have been set up by a group. If no channels are set up, they function as the only networks of communication. Because people are friends, because they usually share the same values and orientations, because they talk to each other socially and consult with each other when common decisions have to be made, the people involved in these networks have more power in the group than those who don't. And it is a rare group that does not establish some informal networks of communication through the friends that are made in it. [...]

Because elites are informal does not mean they are invisible. At any small group meeting anyone with a sharp eye and an acute ear can tell who is influencing whom. The members of a friendship group will relate more to each other than to other people. They listen more attentively, and interrupt less; they repeat each other's points and give in amiably; they tend to ignore or grapple with the "outs" whose approval is not necessary for making a decision. But it is necessary for the "outs" to stay on good terms with the "ins." Of course the lines are not as sharp as I have drawn them. They are nuances of interaction, not prewritten scripts. But they are discernible, and they do have their effect. Once one knows with whom it is important to check before a decision is made, and whose approval is the stamp of acceptance, one knows who is running things.