As on the latest MacBook Pros, the Thunderbolt ports also act as a Mini DisplayPort--same shape.
I have been using a Mini DisplayPort to HDMI adapter on my MacBook Pro's Thunderbolt port for a few weeks now. It works, but I have an intermittent problem with the adapter getting hot (very warm to the touch) and the display cutting in and out. I've read forum post on Apple's support site about similar problems, but no about the adapter getting hot.
I think there are still a few bugs to work out with the Thunderbolt/Mini DisplayPort jacks.
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