During the editing process for the book, it was pointed out that the purple and white information card logo hadn't officially 'cleared' the related legal checks (i.e. making sure the logo didn't resemble an existing piece of work by a third party) When I was writing the book, the draft that went to the editor actually included the purple and white icon. As the book went to press, the icon still hadn't cleared legal, so we decided to play it safe and use the unofficial icon that had been adopted by the community.

The good news is the purple and white information card logo has cleared legal, as Mike posted earlier in the summer. The goal is tha this icon will be as ubiquitous as the orange and white rss logo on sites, and a consistent marker to identify that information cards are accepted on your site. Below I've re-posted the icon in a multitude of sizes.

The guidelines for the use of the icon, a frequently asked questions document, a set of png images of the icon rendered in a range of sizes, and the original artwork in Adobe Illustrator format are all available together in a download package.