User blog comment:Bovell/New Battlefield 3 Multiplayer Gameplay Trailer/@comment-4092510-20110721235629/@comment-4092510-20110722032732

3D spotting is pretty much locating the position of an enemy, vehicle, and etc. When someone has been spotted, an indicator(red triangle) will appear over their head for a certain amount of time. It's useful because it allows you to pinpoint enemies and let others know where the enemy is. It also helps with communication since you don't have to physically yell out the position of the enemy. To spot someone, you have to press a button while you're aiming down your sight on that target.