App Store Previews Now Showing on Twitter

Twitter has integrated App Store previews into its website for tweets containing links to iOS apps.
If you tweet a link to the App Store, Twitter.com will automatically show a preview of the app with a description and screenshots.
This new feature allows for easy viewing of apps in tweets before being redirected to iTunes. The previews are only available on Twitter�s website�
Macgasm points out Twitter�s new feature,

�Much like iTunes music, Apple has brought apps directly to the Twitter website. If you use Twitter�s web application instead of a native Twitter client, you�re going to start noticing direct links to purchase and download apps from Apple�s App Store.  The listings also now come complete with screenshots and app descriptions.�

I tried tweeting an App Store link with a shortened URL, and Twitter still recognized the iTunes link.

The preview window is only viewable when you click on a tweet through Twitter.com, don�t just click the link in your timeline.
Kudos for such a nifty feature, Twitter!