Shacknews has confirmed that THQ's Homefront will an online pass designed to discourage sales of used copies of Homefront. While you will be able to play all the online maps without the pass you will only be able to reach level 5 (out of 75), and thus you won't be able to access all the unlocks and things that come with a higher level. The pass comes included with every new copy of Homefront and can be purchased separately for $10 if you happen to buy a used copy.
THQ has previously employed online passes in UFC Undisputed 2010 and the latest WWE offering and by the looks of it they are sticking to the same tactic for now. Are you bothered by online passes? Do you buy used games?