Eavesdrop

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.

Tactics

 * 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 or text chat, which the Eavesdrop ability of course doesn't pick up.
 * 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.
 * Another possible use of it would be to mute all of your teammates and just use the perk; upon hearing a voice, you will know an enemy is near. This can be very helpful if an enemy is very chatty or has a broken mic (constantly providing a buzzing noise to guide you). Although more effective than using it for hearing enemy tactics, it is somewhat limited because any people on your team will need to be muted to make sure that the voice is that of an enemy, depriving you of their helpful game info, if any (this also means that you cannot use Eavesdrop in this way if you are in an XBox Party or playing with friends). Furthermore, anyone who has just joined the game must be muted.

Trivia

 * 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.
 * Eavesdrop is absent from the Wii version of Modern Warfare due to the lack of voice chat.
 * The perk is underused because most of the time, players chat about something other than the game at hand.
 * As seen in game menu source files, Eavesdrop was originally Tier 1 perk.