Out of character knowledge is information that your characters do not know, but you the player do know.  A good 90% of the information presented in Ubique's Weekly is out of character knowledge.  Again, it is a publication written by players for players.  A general synopsis of the previous week's happenings in play-land.  It is highly unlikely that your characters would be privy to the information contained within, but it might be possible that somehow they could learn about it.

For instance: Betty Boobstar plays with Peter Longhammer on a daily basis, but Betty can't be online all the time like Peter can.  So Betty reads UW to find out what she missed when she was otherwise preoccupied with offline activites.  She reads an overview of what Peter's character did during the week to discover that he bought her character a shiny new pearl necklace.  Betty's character certainly won't be aware of this, because Peter's character wanted it to be a surprise.  But now Betty should probably get in touch with Peter to find out when they can play out the scene of Peter's character surprising Betty's.

See how that works?