card

A  card  in the context of the indieweb are small information summaries—often summaries of specific, external web pages.

IndieWeb Examples
For the moment, current indieweb work is focusing on developing a simpler alternative to all the silo-specific card approaches. See:
 * indiecard

Apple Passbook
Apple
 * (Apple Passbook API/format reference needed)

Facebook
Facebook uses OGP and other markup on a page to parse data to shows summaries of pages linked to in Facebook posts in a "card" like presentation.

Examples of Facebook "cards" displays:
 * link-preview for the first URL in a post
 * hovercard shown when hovering the mouse pointer over someone's name, including face, name, friendship status, etc.

Google now
Google now uses cards as a method of display of various information - see the Google now page for more overall, and http://www.google.com/landing/now/#cards for examples. Some of Google now's cards appear to be produced from recommendation engines.

Twitter Cards
Twitter uses OGP and their own proprietary meta tags to provide Twitter Cards functionality in tweets.

Embedly
Embedly has a card embedding service at http://embed.ly/cards that parses other sites, and generates a card that you can embed, using a variant of oEmbed.