For the third year in a row, Yahoo Labs took the Best Paper Award win at the ACM International Conference on Web Search and Data Mining (WSDM 2011), held February 9 to 12 in Hong Kong. “Unbiased Offline Evaluation of Contextual bandit based News Article Recommendation Algorithms” by Lihong Li, Wei Chu, John Langford, and Xuanhui Wang won the Best Paper Award. The Best Poster Award also went to Yahoo scientists Flavio Chierichetti, Ravi Kumar, and Prabhakar Raghavan for “Optimizing Two-Dimensional Search Results Presentation.” Yahoo Labs had a strong technical presence overall, with seven accepted papers, eight accepted posters, and various members on the program and organizing committees. The two keynotes were given by Christos Faloutsos of CMU and Harry Shum of Microsoft. Faloutsos talked about pattern mining in large-scale graphs, while Shum discussed Bing’s model of user intent. Attendees observed a heavy emphasis on data analysis, a growing popularity of work on interpreting query-logs as time series, and interesting contributions on analyzing the shape of bursts (clustering time series according to their shape). There were also interesting papers on user behavior analysis, and Twitter and other social media. Attendees raved about the conference banquet, which was held at the Jumbo Floating Restaurant in Aberdeen Harbor, a popular dining spot among celebrities and politicians. They indulged in the traditional Chinese dish, “Beggar’s Chicken,” consisting of a whole stuffed chicken wrapped in layers of lotus leaves. Yahoo Labs accepted papers: Efficient Online Ad Serving in a Display Advertising Meta-Exchange Kevin Lang, Joaquin Delgado, Swaroop Jagadish, Amita Gajewar, Dongming Jiang, Michael Bindeberger-Ortega, Bhaskar Ghosh, Shirshanka Das, Arathi Seshan, Chavdar Botev, Sunil Nagaraj and Raymie Stata Who Uses Web Search for What? And How? Ingmar Weber and Alejandro Jaimes Optimizing Two-Dimensional Search Results Presentation Flavio Chierichetti, Ravi Kumar and Prabhakar Raghavan Unbiased Offline Evaluation of Contextual-bandit-based News Article Recommendation Algorithms Lihong Li, Wei Chu, John Langford and Xuanhui Wang Dynamic Relationship and Event Discovery Anish Das Sarma, Alpa Jain and Cong Yu Identifying 'Influencers' on Twitter Eytan Bakshy, Jake M. Hofman, Winter Mason and Duncan J. Watts Batch Query Processing for Web Search Engines Shuai Ding, Josh Attenberg, Ricardo Baeza-Yates and Torsten Suel Yahoo Labs accepted posters: Bid Generation for Advanced Match in Sponsored Search Andrei Broder, Evgeniy Gabrilovich, Vanja Josifovski, George Mavromatis and Alexander Smola Web-Scale Table Census and Classification Eric Crestan and Patrick Pantel Document Assignment in Multi-site Search Engines Ulf Brefeld, B. Barla Cambazoglu and Flavio P. Junqueira Adaptive Bootstrapping of Recommender Systems Using Decision Trees Nadav Golbandi, Yehuda Koren and Ronny Lempel Scalable Clustering of News Search Results Srinivas Vadrevu, Choon Hui Teo, Suju Rajan, Kunal Punera, Byron Dom, Alexander Smola, Yi Chang and Zhaohui Zheng Learning to Re-rank Web Search Results with Multiple Pairwise Features Changsung Kang, Xuanhui Wang, Belle Tseng, Yi Chang and Zhaohui Zheng An Algorithmic Treatment of Strong Queries Ravi Kumar, Silvio Lattanzi and Prabhakar Raghavan Enhanced Email Spam Filtering through Combining Similarity Graphs Anirban Dasgupta, Maxim Gurevich and Kunal Punera