I find it funny that people are quietly panicking over the membership decline here, especially given the fact that the great game engine of Facebook, Zynga is falling like a rock and the management and the staff can't leave the building fast enough.
I used to work for a company that had an online service known as the “Multi-Player Games Network.” It had a principle game galled “Kingdon of Drakkar” and a few other board games (that were developed by me) that included “Empire Builder” and “Operation Market Garden” that could count on a dozen active players (needless to say, our revenue came from KoD with membership in the hundreds of players online at the same time). When the company was sold to another small company that didn't seem interested in KoD back in 1999, the designer of the game bought back the rights to the game and hosted it on his own severs. He's still running the game today.
Another game was created by an author to promote his political science fiction book “Nationstates.” Over the course of the years, his original hosting service tried to illegally copy his game and the United Nations sued him because his game had a UN organization in it, but he's been running the game for 10 years now.
So what does this mean? It means that it is possible to run a game service “under the radar” if you really want to run a game service. You will never see massive stock options, or huge profits but it is certainly possible. The CC operational model is based on casual play, which means that it is a low server resource draining game. Thus with the possible exception of hardware end of life, this could easily go on for years with a limited (paying) membership base.
That isn't to say that it isn't possible to promote this game, but such promotions are not always cost effective.