Lots of people like MMORPGs. Lots of people can't play them for long at all. The weird thing is, it's almost impossible to tell which is which. I mean, it's relatively easy to tell whether someone is likely to like RPGs, or FPS games, or sports games... but a MMORPG? It's all over the map. A lot of people who don't like any computer games like MMORPGs, whereas a lot of people who love RPGs hate them (like me).
Well, here's a new theory that I came up with today, thanks to a too-scattered conversation about MMORPGs:
In a MMORPG, there are a lot of distinct "play loops" - mining ore, or killing monsters, or trying to find gall bladders, or seeing the world, or whatever. However, each of these play loops is painfully bland. Even players who like a given play loop would find it unbearable if it was the only play loop in the game.
Fortunately for Blizzard's coffers, they aren't the only play loops in the game. There are dozens of these crappy little play loops, and sometimes even multiple copies of the same play loop at the same time.
The loops are built with a kind of loose reward structure - this has the potential to give you statistical upgrades, this has the potential to be worth money, this has the potential to give you skill points, this has the potential to let you see something cool. Each play loop feeds into one or two of these basic reward structures, and feeds out of these reward structures. Moreover, in some ways, the rewards can be transfered to one another, and therefore considered a coherent "power level".
While the loops are not actually connected to each other, they are all connected through this central reward system. Moreover, you often stay only a few minutes on any given play loop and switch opportunistically between them - mine a few things on your way to the auction house, or whatever.
Also, a lot of people tend to do metagame simultaneously. Chatting or surfing the web while grinding some boring part of the game. This is essentially the same thing: shifting between play loops keeps shallow loops from getting too boring.
I think that the reason people who like MMORPGs like them is that they have the capacity (or tendency) to intertwine these play loops manually. Part multitasking, part value abstracting, they like playing with many simple, loosely joined play loops.
This has the advantage over more rigidly defined games in that the player can choose pretty much any play loops they feel interested in at any time. However, it suffers in that any player who does not multitask or value abstract cannot play the game.