I’ve started following what’s going on with the Azardi project. I haven’t fired up my Windows emulator to try out the software (it’s in a very early release) but I do like the thought they’re putting into it, and using WebKit is exactly the right approach. I say these things not just because Richard has very nice things to say about Bookworm. (But I will gently remind them that if they’re releasing it under the GPL license, they must post the source code!)
One of my early design goals for Bookworm was that it might become a reference implementation for ePub. Fortunately, ePub adoption happened too quickly, and inundated with non-conforming uploads, I changed direction towards accepting a wider range of conformance. (I do still try to follow the IDPF guidelines for how a reading system should or should not behave, and where a reading system is explicitly forbidden to do something, I don’t.)
What I’ve learned from this experience is that you don’t release a specification without a strict reference implementation. Adobe Digital Editions has become the de facto reference for many ePub producers and in this context it’s the worst of both worlds, neither implementing all the behaviors of the specification nor strictly enforcing its prohibitions. I hope the Azardi folks stick to their guns and produce at least a strict mode. And post the source!