I have a reasonably successful FB app. It's not farmville or scrabulous, but it does get a more-than-moderate amount of social traffic.
Conjoined with the popular FB app is a not-as-popular public version on the www.
You know what I'm getting tired of? Changes to FB's API. Every few months, my app breaks, I get hate mail from my users, and I need to go in and perform emergency surgery on the code. Yes yes facebook has their developer wiki/news and they have started to announce things in advance, but come on. I built this thing two years ago, it works, I've fixed it a dozen times already, so leave it the heck alone.
What I would really like is for more people to stop using the FBML version, and switch over to the public one.
So here's my strategy:
1) publicize the public site prominently on the FB app's canvas pages
2) offer increased functionality on the www version, neato features that are not available in the FBML one
3) make it easy for FB-authenticated users to switch over to the www one, still authenticated. Hook it up to FB Connect.
1) FB is the primary way that strangers discover my app. Honestly there is nearly zero chance of ranking in the SERPs with this thing.
2) As mentioned, the FBML version breaks every few months.