Are people grouped into leaderboards based on when the player logs in? My guess is that it probably doesn't quite work this way or partially works that way at best....but some players think that you are thrown into a group of players logging in at the same time so I thought I would ask. Is it completely random and predetermined?

I've contacted a lot of like-minded players about Leaderboards and there is a tremendous groundswell for wanting to be placed into leaderboards with other like-minded players/friends/neighbors... or attempt to at least.