Certain powers cause damage without specifying any conditions about how that damage is dealt. Consider, for example, the following Barbarian
Rage Daily Powers:
Earthquake Dragon's Rage
Effect: whenever an enemy hits you, you deal thunder damage equal to your strength modifier to each creature within 5 squares of you.
Desert Wind Rage
Effect: at the start of each of your turns, you deal 5 + your strength modifier fire >damage to each enemy within 5 squares of you.
Does the Raging Barbarian need line of sight or line of effect to a target to deal damage to it? For example, if an enemy is on the other side of a wall but within 5 squares, do they take the damage?