I have been playing a web-based MMORPG: 
Realm of the Mad God produced by Wild Shadow Studios.  This game is even more retro than Clan Lord (if you can believe that) as the graphics are a blocky, pixelated throw-back to the old Legend of Zelda game.
This game does a number of things very well:
- It allows many people to play online using just a web browser (and the Flash plugin).
- It is free to play.
- It relies on microtransactions for revenue.
Long have I dreamed of seeing Clan Lord move from an application-based game to a web-based game, and RotMG is an example that such a transition is possible.  One of the major downsides is that there is 
rampant cheating within this game – apparently it is quite a simple matter of writing an add-on which enables one to boost the character's stats, granting unlimited health/speed/defense and such.  It may be possible to move from an application-based format to a web-based format but, based on the current security technologies, it does not appear that such a transition would be beneficial for Clan Lord.
Cheating aside, RotMG is still a fun game to play.  I have found myself repeatedly spending a couple of dollars for a few vanity items.  I have 
thought about microtransactions in Clan Lord, but in its current format, CL doesn't really 
need microtransactions.  If CL were ever to become a free-to-play web game, then perhaps such a business model could be reevaluated.
Maybe I should learn how to write Flash games for the web!