Call Of Duty 4 : Modern Warfare
Eavesdrop is a Call of Duty 4: Modern Warfare 3rd tier perk that gives a player the ability to listen to enemy voice chat. Eavesdrop will only work when a player is in close proximity to enemy players. A player will be able to hear both allied and enemy voice chat simultaneously.
Eavesdrop is perhaps the only perk which is renowned worldwide as useless because enemies can simply mute a player, preventing them from being heard by that person.
It is also ineffective because players will often be in parties, not have headsets or at least not talk about anything which would benefit the user, such as where other players are going, tactics etc.
On the PC, it's nearly useless, as many players use different programs on the side to communicate, which the Eavesdrop ability of course doesn't pick up.
On the PS3 version eavesdrop is more useful because 70% of players have microphones.
Eavesdrop is not useful on the Xbox 360, because the NXE Party system is enabled.
Eavesdrop seems to be more useful in hardcore, because when throwing a grenade or firing into a crowded area, a player with a microphone is likely to inform his teammates before performing the action, and thus notifying any nearby player with eavesdrop.
Eavesdrop is absent from the Wii version of Modern Warfare due to the lack of voice chat.
The perk is almost never used because most of the time, players chat on about something other than the game at hand.