Dungeons And Dragons Online: DDO News: Quests

Xundau has two posts discussing a little bit about the quest system. The first of the two discusses objectives and bonuses during quests:

Our dungeon quests generally have one or more primary objectives, and can have a number of secondary objectives as well. So for instance, the primary objective of a dungeon might be to recover the hobgoblin chief's plans. But you might have a secondary objective to free his kobold slaves, and another secondary objective to destroy some of his supplies.

Only the primary objective(s) needs to be completed in order to successfully finish the quest. Completing secondary objectives will increase your the xp you receive, and possibly reward you in other ways as well.

You can read the first post here.

The second one discusses repeating quests:

Some quests will be repeatable, and some won't. Similarly, some quests will have random elements (monsters, traps, placement of quest objectives, etc.), and some will be mostly fixed. I'd imagine that there's some correlation between these (i.e., repeatable quests would tend to have more random elements), but I'm not sure.

That post, from the same thread, is available here.