City-Building MMO

I was playing a little Caeser III last night (my personal favorite city building game) and I started wondering whether anyone was attempting an MMO based on city building. It just seems like if there's a gaming genre (RTS, FPS, SRPG, etc.) someone out there is trying to make an MMO out of it.

After some searching, it appears that Cities XL is the most likely contender. They just released a trailer last week so I know they're still kicking and they seem to have a relatively small but rabid forum fanbase.

How do they plan to make city-building an online community experience? From the FAQ:

"Build your cities in a virtual world populated by other subscribers.

This allows you to cooperatively create a living online community
Trade with others, specialize your city in specific activities such as tourism, entertainment, business development, recycling management and more.

Visit other cities and host events for others to attend and enjoy.

Cooperatively create a booming metropolis teeming with life and businesses.

Participate in competitions and enjoy a calendar of events that will keep you coming back to your planet.

Share your in-game experience with friends through a companion community website."

I'm not sure how succesful this endeavor will be but I enjoyed reading the blog postings and browsing the forums so I bookmarked the site to check back every 3 months.

Oh, and if you are a city-building nut and you are interested in the game - you can tell that the devs really read every forum thread and incorporate community suggestions. So get posting.