Ascertained via a robust scientific method. No Bainbridge or Kerr, who are also leading authories in their areas, as well as bloggers? Curious indeed.
UPDATE: Reader Jason Walta may have solved the mystery: "I think the only discernible guiding principle for inclusion on the list was 'Here Is A Person You'll Recognize From the Internet!'" That certainly might explain some of the the inclusions, but doesn't explain the omissions of the folks noted above. I guess we'll just never get to the bottom of this.