Hacker News Reader

We can try it ourselves. Just log in and go to http://www.facebook.com/deactivate.php

The 5 that show up for me are people I recently friended (unfortunately all dudes)

Random selection of people I've been in pictures with.

edit: they've tagged me in their photo, or i've tagged them in mine. age of picture is all over the place, so not just recent ones.

It appears to be completely random. I got entirely different selections on two separate clicks.