Entrecard is a blog networking and advertising tool. The concept is simple. Join the Entrecard network, create an advertisement graphic, and then place the code on your website. The result will be the Entrecard widget which pulls your graphic from the Entrecard website. Other Entrecard users can drop their “business card” on your site and earn credits for doing so. Entrecard credits can then be used to purchase advertising space on other Entrecard member websites.