Twitter cards have been around for some time now. They enable you to attach media to your tweets that link to your content. If you know your way around HTML and PHP, you can easily integrate Twitter cards with your site easily. But just like most other things, you can integrate these with WordPress by picking up the right plugin. JM Twitter Cards is one of those.
JM Twitter Cards adds Twitter Cards to your website. If you have a plugin such as SEO by Yoast installed, you won’t need this. This plugin does let you add your information and choose the type of card you would like to add to your site. The script lets you add site description and define a fallback image on the Options page.
JM Twitter Cards is not perfect but does integrate Twitter Cards with your site. It could prove useful, especially if you are a big fan of Twitter.