Hello, I have been browsing your website and I am interested in the idea you have here. It sounds like this could be a great way to share components of projects together.
I am working on a project with similar usage to your ShoppingList program. What I have (sorry no website yet) is a bit more advanced that what you are showing on your site and I plan to expand this into even more functionality. I am very excited about your OpenIntents idea because this opens up a way to share reusable data across applications as well as plugin functionality between projects.
Locations is a great example of where we need to be sharing data, people don't want to have to keep entering in the location of their house every time they get a new application. Also if someone comes up with a new type of service, the barcode scanner is a great example of this, other people can integrate that functionality into their app once the user has downloaded that piece.
Great idea, I will be looking at integrating this as an option in my application. Keep up the good work.