The May 2015 special issue of The Annals of the American Academy of Political and Social Science will feature articles by Sandra González-Bailón and Sijia Yang. González-Bailón’s article “Signals of Public Opinion in Online Communication: A Comparison of Methods and Data Sources” was co-authored by Georgios Paltoglou. Yang’s article “Constructing Recommendation Systems for Effective Health Messages Using Content, Collaborative, and Hybrid Algorithms” was co-authored by Joseph N. Cappella and Sungkyoung Lee.