Point blank area of effect (abbreviated PBAoE) refers to skills that affect anything within a radius centered around the user and sometimes cause damage over time (abbreviated DoT). The presence of a damage over time component forms a "Pulsing Point Blank Area of Effect" skill, while an absence of damage over time is simply a "Point Blank Area of Effect" skill (or some players may call it a PBAoE Direct damage). Generally point blank area of effect spells that do damage over time will do more damage than those that do direct damage, provided that all of the damage is actually dealt.
Pulsing Point Blank Area of Effect or PPBAoE (or PBAoE DoT)
Examples: Symbol of Wrath and Lava Font. After casting these skills, the effect will remain at the location cast, regardless of the caster's position. In PvE, since the 2005/11/10 update, henchmen and most creatures flee from AoE skills that do damage over time, but generally take 2-3 seconds of damage before fleeing.
Point Blank Area of Effect Direct Damage or PBAoEDD
Examples: Inferno and Signet of Agony. These skills will instantly do their damage to nearby foes, and won't cause foes to flee like Lava Font will. However, repeated use of these skills in a short time has the same effect as a DoT spell.
Pulsing Point Blank Area of Effect Enchantments
Example: Balthazar's Aura. These skills will place an enchantment on a target ally which will give them a pulsing PBAoE Direct damage effect that will change locations as the ally moves. These abilities still cause foes to flee like other Pulsing Point Blank AoEs.