[keanzu]

My guess is that flags are responsible for a lot of weird movement in the front page ranking. You flag an article and it starts losing spots - a number of people do it and the article can die entirely. The flag count is hidden to prevent bandwagoning but is an important signal. Thus front page posts move in mysterious ways as if guided by an unseen hand.

Well they are and the hand is users flagging posts. Plenty of times I've seen

  Article A, 2 hours, 50 votes
  Article B, 1 hour, 100 votes

Where A is ranked above B despite being older and having fewer votes (the signals we can see). I think the missing link is flags. I bet if we knew the flag count the front page ranking would make more sense.