I followed the same path of Unfuddle to FB. I found Unfuddle to be an uninspired clone of Trac, however, which is exactly why I chose it -- I had used Trac and wanted a hosted version of that.
I liked unfuddle and assumed they would add features, however after 1 year of usage it was clear that they were not big fan of features and didn't add anything useful (at least anything useful for us). Which always amazes me, how a startup can spend a year without adding any good features or just add 1-2 minor features and try to get away with it...
Adding features is hard work, risky, expensive, and sometimes counterproductive (!).
It's hard work, because you need to change an existing, working piece of software with new code, and deploy it. Including possible database changes.
It's risky. Deploying a new version of your software might introduce nasty bugs, huge usability problems, or you might change the way things worked before, actually displeasing a lot of users.
It's expensive. Programmers aren't cheap. Then you need testing, QA, ticket triage... all things that cost a lot of time, and money.
Counterproductive. Your new features might only benefit a tiny portion of your userbase, and might not attract new customers. They might break your existing model. And so on.
Once you've reached a good feature set, doing continuous development is more of a life choice, rather than a business decision that makes sense.
