How does facebook determine who shows up in your chat side bar?

[Cookoo]

I know how they *say* they do it.. but, theres people on it that i never interact with over facebook, but spend alot of time with everyday. and then theres people i think about alot and havent interacted with in years. so how do they take the places of people that I interact with more frequently, but dont care about?

anyways, my theory is that it has to do strictly with either how much you're on their profiles, or how much they're on yours.

my question: WHAT DO YOU THINK?

[Ayan]

It detemines with manythings

chats
posts on walls
tags
messages
games

also matters if both your cities are the same