What does an mmorpg need to be successful?

Basically my question is what elements/other things does a good mmorpg need to make people want to play it. Like WoW for example it has story and stuff. So basically im just asking for kind of like a list of what a good mmorpg has in it and needs. Thx.What does an mmorpg need to be successful?
It needs the World of Warcraft.What does an mmorpg need to be successful?
Firstly and most importantly a large selection of customization equipment(eg, armour, weapons, pet's,etc). it also needs to have large skill/spell section in it. you're obviously going to need plenty of quests, but try to make it so that you not doing the same thing every quest (i.e killing enemies picking up remains and delivering them to the quest giver). and it needs have somehting that no other rpg games have so that it makes it unique, and you'll need to work out what that is yourself.



hope this helped



oh also pvp can't forget about that