I want to make a comparison between real estate marketing and game marketing in this "all to similar" world in which we live.
What is the difference between a hamlet and a town? Well, there may actually be one in the technical name- but looking beyond the potential "Joe, a town is not actually a hamlet" mentality is that the perceived size of a game matters to the value of the product. A hamlet sounds cozy and friendly, a town is just a town. If you describe the place you live in that cozy and small villa motif the value of your place increases. Further, if it LOOKS like that (regardless of actual population) the value increases more.
What am I getting at? Too often I find all these games which are not cozy and not small villas. They actually try to market a quasi-metropolitan ideal. A HUGE world FILLED with people where you're actions are INSIGNIFICANT because there's always someone way higher level than you doing important stuff.
Ok, nobody actually describes it like that, but essentially that is what they are doing.
When determining your design of the game and the way you deal with community and interactivity consider trying to minimize the impact of having large populations. Sure, you want 100 million players, but you want each player to feel like they are a member of a bedroom community. Figure out a way to have both and you'll find yourself rolling in the riches.
The reason behind this is simple. People like to feel special. You can't feel special if you know how small you are. The community needs to build people up, even if it is in some small way. They don't all need to be kings of kingdoms, but to have something percieved as unique- the best blacksmith in a kingdom, the strongest warrior, the guy who can drink more ale than anyone else... WHAT it is doesn't matter. What matters is IDENTITY. People need identity in online communities; and the current cookie cutter designs never seem to deliver.
So give that one some thought. How do you give 1 million players an individual identity that goes beyond an avatar....
Good luck, it ain't easy ;-)