Daily Quests are from the Billboards around the world, there is usually one in every city. Players can complete ten daily quests each day. They involve either killing mobs for daily quest items or just killing mobs. There is the occasional quest where you just have to run and deliver a package. Daily Quests will also give you 10 Phirius Tokens per quest.
Storyline Quest Chains
The other quests are ones you will get from NPCs. They unlock as you level up, and involve many things with many rewards. Players can hand in quests with a level-gap of 10 Levels, e.g a level 29 secondary can't hand in quests (level 40) in obsidian, but a level 30 secondary can (dailies are an exception).