Also Player Added Fees.
Any added money to freerolls or guaranteed prize pools is divided amongst the players.
So if they add $100 and there are 10 players each player is charged -$10 on the gross rake.
Charging people to play in free rolls should be illegal, but some
rake back is better than none.
To see charges just click "
Rake Tracking". Then click on the "Full Tilt Poker" hyperlink.