How does Facebook handle the chat list?

[Chronicle]

Facebook aims to select people according to how good friends you are with them. The idea is that you will be more likely to see your sister and your best friend popping up there than you will be to see Sarah from school whose you never see or talk to on Facebook.

Facebook bases the selection on public interactions you have had with those people in the past one and a half months.

There is an algorithm that decides the friends list on your Facebook page which uses a variety of other bits of data - but that all of them are public.

>> the number of photos you are both tagged in [apparently this is upweighted a lot]

>> public interactions: how often you write on their on their wall, how often you share links with them, how much you comment on their photos or status updates

>> the number of friends you have in common

>> how long you have been friends [that would explain a few randoms from the past turning up on my wall yesterday]

Hope this give you a good idea...

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