My biggest fear for my JAAJAX library is that it will be misused by someone to build an application in the browser that really should have been a full windows app. In fact I can almost guarantee someone will misuse the library in this way.
So why release it? Simple, technology can not be stopped and shouldn't be; I'm thinking of the RIAA in their woes... if they embraced the technology early on would they be in the state they are in now trying to stop people from using technology to trade songs? (NOTE: I'm not saying that peer-to-peer song trading is a good thing or even an ethical thing, just that technology has enabled it... technology that the RIAA could have shaped to some extent).
I figure by releasing my library that I maybe I can influence some of you who will use the technology. Maybe I can help write some of those best practices that IMHO don't exist today. AJAX is exciting, but we need to use it for the right jobs and not use it as a sledgehammer to do everything.