I guess that having [commented on the blog][1] that answers would be better here than on the blog, I might as well open a question...

This question is designed to encourage us all to think about what we want to use a potential API for *before* making specific feature requests. Ideally, answers would be structured as:

> **I want to build...**  
> ... an Android widget which can show me my current rep, badges, and rep for the day, across
> multiple sites
>
> **For this, an ideal API would...**  
>
> - Let me query multiple fields in a single request
> - Let me specify multiple sites (with multiple user IDs) in a single request
> - Access badge, rep, rep-per-day information

Other answers may well be much more detailed, of course, but hopefully this gives the gist of what I think might be a useful *type* of answer. Things like useful formats (JSON, XML) would be interesting to [Jeff Atwood][2] too, I'm sure.

  [1]: http://blog.stackoverflow.com/2010/01/what-would-a-stack-overflow-api-look-like/
  [2]: http://en.wikipedia.org/wiki/Jeff_Atwood