Lightning Damage

Lightning is one of the types of damage in Diablo III. It is blue/white-tinted in appearance.

Lightning damage is dealt by a wide variety of character skills and spells, and can be added to skills with runestones. It is also a common modifier found on items.

Numerous monsters cast Lightning-based spells or add lightning to their attacks. Bosses may manifest it with the Electrified boss modifier.

Lightning damage can be resisted, as well as reduced or absorbed, but not blocked (except in Charged Bolt form).

Critical hits scored with Lightning damage stun targets for 2 seconds.

Diablo III Damage Types

A wizard casts Electrocute.

Blizzard's @Diablo Twitter feed added some clarification about damage types in posts made in early December 2010.[1]

any change in the range of damage types to include holy, shadow, voodoo or anything else to match the classes? —Scyberdragon

Damage types will likely change some but are currently Physical, Fire, Lightning, Cold, Poison, Disease, Arcane, and Holy. —Diablo

Whats the difference between poison and disease damage?—WickedBubba
Disease has a damage debuff (both intake and output), and poison has a health debuff (regen/heal). Subject to change of course.—Diablo

Is there much difference between poison and disease? They’re both internal maladies that hurt over a period of time.—Grug

Fairly significant in their difference, but both countered with a single resistance. Damage/resists aren’t design complete though.—Diablo