GiantBomb has written
In second person point of view, the action is shot from the perspective of a character who is not the protagonist. To qualify, the player must continue being in control of the protagonist, but see action through the eyes of another character which he can interact with.
In video games, this kind of second-person perspective is mainly seen in text-based adventure games, such as the Zork series and Hitchhiker's Guide to the Galaxy. It can also be seen in some role playing games to explain an action your character has performed, for instance: "You use Magic Missile on the trolls". The use of second-person perspective can help players feel as if they are actually the character they are controlling.
The other type of second-person perspective in games mainly has to do with camera angle. In this type, the main character (the on being controlled by the player) is seen through the eyes of another character. For instance, the first boss of Battletoads has the player fight the boss through the eyes of the boss. The player is still in full control of the main character (as being able to move the main character, mind control does not count), but all the action is seen through the boss's perspective. Super Mario 64 was one of the first games where all the action is seen in a second-person perspective, through the camera of Lakitu.