Area damage over time
From Guild Wars Wiki
Area damage over time or ADoT skills are skills which inflict periodic damage in an area. Examples include Fire Storm, Flame Trap and Balthazar's Aura. Area health degeneration skills are also sometimes grouped with area damage over time skills due to similar functionality, however they are not technically area damage over time skills, as degeneration is not technically damage.
[edit] Monster scattering behaviour
ADoT effects can cause monsters to scatter. This generally isn't a concern in Normal Mode, as monsters can take quite a few hits before scattering, however in Hard Mode, monsters scatter far more quickly.
