Structured Internet Client
Like browser, but structured, based on high level protocols?
For all intents and purposes, browser can be thought of as "Unstructured Internet Client", because it can render arbitrary UI. However, the Internet data is getting increasingly structured. This can be seen in the shift of paradigm from creating custom HTML pages to creating public APIs as the main entry point to what application has to offer.
The idea of structured internet client, is thus a client, that defines protocols for ranges of similar apps.
An example of a structured multi-protocol client, is Trillian, a multi-protocol messenger. However, it is not only chat that has the need for very similar UI. For example, E-mail had same UI, regardless if POP or IMAP protocol was used. Also, there are many other things that are similar, like: shopping, video viewing, forums, etc., that today have hundreds of unique apps, that rely on their APIs, but coherent open-source UIs could be developed to allow the display and interact with such common content.
If a general purpose client for Internet's structured data is created, then everyone's day-to-day work may be simplified.