Twitter just wrapped up a developer shindig at its San Francisco HQ and trotted out three new content preview cards. When a user links to a page with Twitter-specific markup, a tweet will feature an application's name, icon, description, rating and price within the freshly unveiled App Card and link to its Google Play or App Store page, to boot. Product Cards on the other hand, highlight merchandise with an image, price and even ratings. When tweets link to a photo gallery on the web, the social network will use a Gallery Card to display a collection of four photos, indicating that it points to an image set, and not just a lone picture. The firm rounded off the updates with "mobile app deep-linking," which means that tweets can sport a download link for the app which was used to publish them. Flickr, Foursquare, Path, Vine and others will make use of the new features when they launch, which should be tomorrow according to word from the coder get-together.