When I saw that Mafia Wars was one of the most popular games on Facebook, I went to check it out, and before long thought "Wow, this is just like forumwarz except with mafia." Apparently html rpgs are now a viable genre.

Have you ever considered making more games that are essentially gameplay clones of forumwarz but with different themes? That seems to be a lot of what Zynga has done with their facebook games - Mafia Wars, Vampire Wars, Zombie Wars, etc. Also have you considered social network integration yourself. I hate to suggest such un-innovative strategies but it might work.

Zynga has one trick, that they don't always do well. I would suggest NOT emulating them.