We can confirm today what we didn't know a few months back - Resistance 3's online co-op mode will require a Online Pass in order to function. An online pass is a one time use code included with new copies of the game. Because of this, the two player online co-op mode won't be functional to gamers who buy Resistance 3 pre-owned or rent it from online services like Gamefly. The game's split-screen co-op mode is unaffected by this.
This is the first instance in which a game's co-op mode was locked out because of this growing trend in video game publishing.
To purchase an Online Pass you'll need to visit the PlayStation Network Store and purchase one for $10. This gives you access not only to the game's two player online co-op mode, but the versus modes as well.