[billjings]

That's an interesting point. I think that's a different sense of the word "anonymous," though.

There's a strict sense of the word "anonymous" that is from the tradition of writing: an anonymous letter, for example, or the sense in which 4chan users are anonymous. It means "this person has no unique identity at all, other than what one can infer from this written word." This is the kind of anonymity that e.g. Facebook has fought against with their policy that accounts should have real names.

There is another sense in which "anonymous" is used that is common to all kinds of secret societies, though, and that is simply public anonymity as a member of the society. You don't wear a pin or make it known that you are an active member, except maybe to specific individuals that have need of that knowledge. But within the society itself, you very much have a distinct identity.