Successful simple web based MMORPG

Massively Multiplayer Online Role Playing Games are at the peak of popularity. People like to play with other live players and compete with them. Game producers are gaining more and more profits from that kind of games, giving better and better visual and audio experience in pseudo 3d worlds. Is there a place for a technically simpler web based games?

One of my friends told me to look at the one classic game of that type: Fallen Sword produced by Hunted Cow Studios Ltd.. Game started, as I know in 2006 and today has about 2 700 000 registered accounts. There is probably massive amount of inactive players, but the number is still impressive. As I checked during day there were always above 2000 players online. So people like not only WoW 3D style games.

The main game concepts remind some of popular MUD games, with added graphics, auction house and trade between players suport. You can buy special game money units, for real money using for example PayPal account. Those units called Fallen Sword Points maybe used to boost game character skills or other attributes. Although there is no way out for money as company states in terms of use, in game economics is quite strong. People are playing game for fun, but sometimes are trying to trade game money for little services, like giving temporary skills boosts called buffs, or "selling" fan-art avatars. Those gray areas are acceptable, in other cases the real winner is producer.

The game lacks some responsibility that can be gained through more AJAX like components, but overall speed is acceptable. I'm trying to figure out other interesting features - and ideas for game people may have. I like those kind of the non highest tech but very playable games. I had one web based game started and unfinished prototype in past, so I'm interested in subject from a business point of view too.