Fans can add a badge to their existing Facebook or Twitter profile photos to share and spread the word about Rebirth, the upcoming novel of The Pretender.
Visit this link while logged in (or use the links to log in with Facebook or Twitter if not logged in) and follow the simple instructions and don't forget to "finish cropping" to get the profile pic set on Facebook.With Twitter the badge is automatically set, no cropping required.
I believe there is a badge for websites, but am not sure how it can work for this wiki.
Screen cap from PicBadge to show what screen you get if not logged in.