Twitter just rolled out an unannounced update tonight.
If you've used twitter for any length of time then you probably know that it can pull content from links in your tweets and show them on the twitter website, right? I have seen this work with Youtube, Twitpic, and Tumblr (sometimes).Tonight that feature started working with product listings for iTunes and Amazon.
About an hour ago a friend of mine noticed this feature for the first time. We spent the past hour trying a number of retail sites and so far the feature seems limited to Amazon (example) and iTunes (example).
It only works on the Twitter website, not the apps. But it's still pretty cool.
Update: A reader informed me that iTunes had been enabled months ago, but this i the first I'd seen it.