.
.
.
I don't think there is an authoritative definition of what it means to be a so-called "thought leader" in movement atheism or movement skepticism. I'd say that leaders are those who get to regularly share their ideas, on topics reasonably related to those subjects, with a relatively wide audience. This could be done through videos, books, blogs, live talks, podcasts, standalone art pieces, or what-have-you. Your hardcore professional skeptics and atheists typically do at least two or three of these things.
(Come to think of it, I probably should have thrown institutional support as a factor in there somewhere.)
As to Skepticon in particular, well that's a strange beast. They are making a deliberate effort to bring in
speakers we've never seen before this year. Hope to see you there, Scrut.