We have had Twitter Card support in most of our applications, especially those built on our Tweematic platform for several months now. The support works in conjunction with our short URLs.
Twitter cards are designed to attach rich media experiences to Tweets that link to your content. Below is an example of a Twitter Card enabled tweet. Notice the summary and graphic information that shows up under the 140 characters of content. The flexibility of Twitter Cards allows us to deliver text, graphics and even video content that “breaks” the 140 character limit and does a better job of telling your marketing story!