Mike sent this email around today. I don't know why he didn't post it here already - I know he's not shy so that can't be the reason.
The Medical Museion blog mentioned their blog rank and put a link to a blog ranking site - so I checked it out.
We’re #6, right above them, and higher than any art museums whom I expected would fill the top tier.
To be honest, I have no idea how they figure this out and looking at individual stats further down makes our whole ranking look fishy, but it was neat to see.