After reading about Jenny having her fill of vampires (HA!) I went to comment a hearty Hear Hear. Or is that Here Here? After all, it could being saying 'Look here people' or is could be saying 'I hear you'. So I did what every self respecting autodidact(or not) does, I googled it.
According to this page, the proper term is Hear Hear. It is a shortened version of the proclamation Hear Ye, Hear Ye, dating back to the 1600s or earlier for the purposes of drawing attention to what has just been said and giving agreement.
So now you know.