Social Media Coke Zero dares fans to design the ugliest Christmas sweater The soft drink brand worked with an agency to create a microsite for the promotion. Would-be designers have made some doozies. By Kevin Allen@kevin_j_allenNov. 25, 2013 SHARE Ragan Insider Premium Content To read the full story, log in. Become a Ragan Insider member to read this article and all other archived content. Sign up today Already a member? Log in here. Learn more about Ragan Insider.