Remember how search engines can show nice snippets in their search results thanks to the structured data that webmasters embedded in the HTML of their webpages (RDFa, schema.org, etc)? Additionally, Facebook gains insight about user’s interest through structured data on webpages (i.e. Open Graph Protocol). Now there is a new kid on the block: Twitter.
Twitter recently introduced Twitter Cards, a way to “attach media experiences to Tweets that link to your content.” By adding structured data embedded in the HTML of your webpage, “users who Tweet links to your content will have a ‘card’ added to the Tweet that’s visible to all of their followers.” Basically, Twitter will now have a bit more of information about your webpage in order to know how to make a nice snippet in a tweet.
Via Martin Stone