I'm currently writing a Chrome extension to monitor stack overflow and give user updates regarding there reputation.
As per this question: http://stackoverflow.com/questions/1830767/so-rep-json-not-working, I suspect that the URL for the rep doesn't support JSONP calls (unlike the flair URL).
Is this for a particular reason? or an overlooked bug/thing.
EDIT: I wasn't sure whether to tag this as a bug or discussion.