That is, someone who has passionately assimilated an extremely far-reaching set of beliefs that originates largely from a single, high-status thinker, and who seeks to establish novel communities or institutions inspired by/based around that thinker's thoughts.
Ok, so in the case of Yudkowdky, are we more interested in his thoughts, or his person ? I understand that it's the person who originally voiced the thoughts, but which is more important -- the thoughts or the person ? And what do we do with those thoughts ? Do we pore through them searching for bits of revealed wisdom, or do we discuss and critique them freely, discarding those we deem insufficiently well-supported ? Is it even hypothetically possible for someone to come up with even better ideas than Yudkowsky did ? What will we call ourselves when that happens ?
All these questions are easy to answer in a satisfactory fashion if you call yourself a "rationalist" or a "skeptic" or something of the sort, but they become somewhat difficult to answer if you call yourself a "follower of Yudkowsky's thoughts". It's a matter of emphasis.
In addition, I should point out that I'm not really interested in "establishing... institutions inspired by/based around [Yudkowsky]'s thoughts" -- thought perhaps others might be. The closest thing to such an institution that I can think of would be SIAI, but its mission statement is to develop a friendly transhuman AI, not to follow anyone's thoughts in particular.
I understand that it's the person who originally voiced the thoughts, but which is more important -- the thoughts or the person ?
The point is that the thoughts are so diverse that the main thing they have in common is their original promotion by a single individual. But it really isn't just Yudkowsky's beliefs that have become currency here. Lots of his idioms pop up everywhere, for example. There was recently a Chuck Norris-inspired thread about how amazingly intelligent he is - tongue-in-cheek, but still telling. And there does seem to be an implicit ...
I often seem to run into problems when I use the de facto label for this group. For example, when I say, "I've been hanging out with rationalists lately," I notice that many people immediately go on the defensive. They might ask why you need a group in order to be rational, or they might say that they don't believe that people are inherently rational. Of course, I made none of those claims, I simply indicated that I was hanging out with rationalists.
You might think that "rationalist" is simply a descriptive label, but it carries positive connotations -- and what people tend to hear is "I'm a superior thinker to you," or maybe "I'm a part of this group, which ascribes the label 'rationalist' to itself, to make ourselves seem higher status than we really are."
Why does this matter?
The community doesn't exist in a vacuum; how the community is viewed from the outside matters. As the community grows and as people gain awareness of it, branding becomes important. People talk to each other, and communities gain reputations. Even if you believe that we are a loose collection of individuals, as soon as you assign a name to yourself, that is sufficient to form a group identity.
The people we interact with tend to share similar interests. The population of New York may be in the millions, and yet I run into the same people at different functions without coordination.
The more negative perceptions associated with a group, the more rapidly evaporative cooling of groups will occur.
What to do?
It's far better to talk about good things that you've gained from being in the group. It's better to say what the group does, not what the group is.
But beyond that, it's about time the community picked a better label to use. I have one idea, but I'll hold off on proposing solutions.