From an eCommerce perspective, wishlists are far from the leading edge. Does the world need another one, and more important, is it marketable?
There are several answers to this. While wishlists (or registries) have been a part of eCommerce for many years, it's surprising how few sites actually use them. Perhaps this is because sites tried out a wishlist, discovered that it didn't measurably add to sales, and got rid of it. Yet Amazon continues to enhance its wishlist offering. And in my former role, I talked with many clients that wanted features that our wishlist offering didn't have.
Chief among these desired features was collaboration: not only sharing a list, but allowing other people to update or comment on it. This leads to some interesting questions about managing privacy and control, and I didn't see good answers to those questions in existing products. I think I've got those answers.
Existing wishlist implementations are also tightly integrated with their host site, typically (as with Amazon) accessed via dedicated pages. However, the way that people approach eCommerce is changing: from browser-based collaborative shopping, to the opening of new channels such as social networking sites. To me, the future will be based on federated services, accessed via rich browser apps, and my wishlist service is squarely in that space.
And finally, there's a personal angle: although I've been working with the J2EE stack for 10 years, and even co-developed a servlet-enabled web-server, I've never implemented a production web-application “from scratch.” This project is a way to cement my knowledge, and also produce a template app that can be adapted for other purposes.