Well Daring Fireball seems to have killed this site for now, but here's the Google cache of it:

Amazon has made a good start, but with a grade of (…wait, let me pull out my calculator here…) 73% (a low C) they still have some serious work to do to come up to the standard of accessibility we hope to see for our students.

Useful information for our ongoing assessment of eBook reader software, but more work to do on this front I think.