Generate inline content previews on Twitter.com and Twitter clients by including Twitter Card HTML meta elements for individual posts. All cards are a Twitter Card summary by default. Tap into the twitter_card_properties filter to reference the Twitter accounts of your site or author. Test your site’s Twitter Card display through Twitter’s card preview tool. Filters twitter_cards_properties – act on an array of properties before they are output to the page twitter_cards_htmlxml – override the default treatment of html with xml. XML will self-close the meta void element ( “” vs. “” )