Greta Christina nails it.
So when I say “atheist leader,” I don’t mean “atheist dictator” or “atheist pope.” I mean:
(a) a person who co-ordinates the efforts of an atheist organization or community group;
(b) a person who comes up with ideas for future directions for atheist organizations and community groups, and who persuades and inspires others to move in those directions;
UPDATE: (b.1): a person who helps a group of atheists figure out and articulate their own needs and ideas;
(c) a person who articulates ideas that are commonly held among atheists, who boosts the signal of those ideas, and who shapes those ideas.
But that’s just the conclusion; the process of how she gets there is the nut of the piece, and well worth reading.