Microsoft is not a fertile ground for the growth of such projects. In fact, in an opinion piece over at CVG, the author labels the company and Xbox Live as an "MMO graveyard" where good titles go to wither and die.
Citing MMOs such as Mythica and True Fantasy Live Online as evidence, CVG says that Microsoft's "inflexibility" became the company's biggest obstacle to seeing a title through to launch. Instead, MMO after MMO was canceled, transferred to other companies, or promised and forgotten. CVG says that there is enough evidence to suggest that Microsoft is unsure and afraid of the MMO model, and instead of doing its best to be accommodating to such projects, the company made it all but impossible for original projects or PC ports to come to fruition.
The article is a fascinating overview of the games and issues involved in Microsoft's approach to the MMO market, and ends with a handful of "hopefuls" that will prove that console MMOs can be done, and done well.