I would imagine the names are in chronological order by when people first accessed the page. So the person who has been browsing the Agora longest would be listed first. But that’s just a guess.
Well, I just sighned on and am the head of the list; unless "granthutchison, tcward, dgale, Stargzer, Brad Ross-MacLeod" signed on instantaneously in the moment after I did, there’s a different explanation.
Usually I’m first on my list but the other day Stargzer was.