Twitter cards make it possible for you to attach media experiences to Tweets that link to your content. Simply add a few lines of HTML to your webpages, and users who Tweet links to your content will have a "card" added to the Tweet that’s visible to all of their followers.
The most significant challenge the open web will need to overcome is not technical, it is political.
Welcome to Thimbl, the free, open source, distributed micro-blogging platform. If you're weary of corporations hi-jacking your updates to make money, or if being locked in to one micro-blogging platform tires you - well, then Thimbl is for you!