Why doesn't my twitter card show?


#1

I created the meta tags & the code validated, I got the emails saying my plough.com site is approved for summary & product cards, but I don’t see anything different when I tweet the link.
Here’s the page:
http://www.plough.com/en/articles/2013/may/an-eye-for-eternity
Here’s the tweet:
https://twitter.com/PloughBooks/status/339118645651320833
?