At your prompting I signed up and tried it out.
1. The back button doesn't apply as all links open in a new window, so kudos for bypassing that one.
3. There is no footer, so you PASS #3.
4. As I tab through the page, partway into a second post my keyboard focus jumps back to the first post. Consistently (Chrome 35 Win). It fails #4.
5. I cannot share a URL, though that point may not apply as this is a page behind a login.
6. I cannot jump ahead a few screenfuls, so it fails #6.
7. I only loaded about 20 items, but the memory did increase and will do so even more for longer blog entries. I say it fails #7.
8. I see no option to disable the auto infinite scroll. It fails #8.
9. Have you conducted user tests?
10. Was this feature driven by a clear need or request?
11. Are you measuring (not just tracking) how well this works for users?
Out of 11 items, it passes only 1. Your example fails 5, doesn't apply to 2 more, and the remaining 3 only you know the answer.
I don't consider a ~50% failure rate (or ~10% pass rate) something that covers "a lot" from my checklist.
I'm not sure why you posted it. It's a pretty quick process for you to check it and you have to see it doesn't pass any more than one item, Four items (out of eleven) if you can make a case for your user testing.