Callsigns

Callsigns are a feature of Call of Duty: Modern Warfare 2 and Call of Duty: Modern Warfare 3 and an alternative version of them is seen in Call of Duty: Black Ops as playercards. They are similar in nature to nametags, and are used to help distinguish individual players, who can customize their Callsign according to their unique personal tastes and preferences.

A Callsign features the following elements:
 * Player's Name
 * Title - a background with a word or phrase
 * Emblem - a small picture
 * Player's level
 * Clan tag
 * Level achieved in every Call of Duty since Call of Duty 4: Modern Warfare (Modern Warfare 3, consoles only)

Titles and Emblems are unlocked through a variety of ways, such as completing challenges and prestiging.

Call of Duty: Modern Warfare 2
Players can choose from 570 Titles and 297 Emblems.

The Callsign of a relevant player can appear on the user interface several times at particular events during multiplayer gameplay: whenever a player kills or is killed by another player, when a player completes or affects an objective in a match, when a player is being spectated (including killcams), or when the player calls in a killstreak reward of 8 kills or more.

Call of Duty: Modern Warfare 3
There are 512 Titles and 350 Emblems to choose from.