Cool... thanks for this list. I'll incorporate it in the FAQs.

To answer your questions right here: The only info reported back is the three parameters from window.onerror (error message, line number, file name), and the page on which the error occurred. It's submitted as a regular form POST. There's no distinction between different types of errors - everything that window.onerror catches is posted. I do have plans for an API (and several other features) in mind - it's still work in progress.