The Upshot section of the New York Times recently featured a paper by Chenhao Tan, Lillian Lee, and Bo Pang (CUCS PhD '06), entitled "The effect of wording on message propagation: Topic- and author-controlled natural experiments on Twitter".
The accompanying New York Times quiz, based on the Cornell prototype and algorithm, hit the top 100 retweeted items according to Topsy, whose computation is "based on the number of tweets for each link and the aggregate influence of twitter users who have tweeted the link within the first 24 hours of the first tweet".
The article also mentions a paper by Lars Backstrom (CUCS PhD '09), Jon Kleinberg, Lillian Lee, and Cristian Danescu-Niculescu-Mizil (CUCS PhD '12).