The Third ACM International Conference on Web Search and Data Mining (WSDM 2010) was held at the Polytechnic Institute of NYU in Brooklyn, NY. WSDM is a young conference that has already become a top-tier publication venue for research in search and data mining. In contrast to some of the larger conferences, WSDM is more intimate and single-track, with over 200 attendees from organizations such as Google, Microsoft Research, Yahoo Labs, IBM Research and AT&T. Yahoo Labs had another outstanding presence with 17 accepted papers, and winning the Best Paper Award out of a total of 45 accepted papers. “Cumulating Relevance: A Model to Estimate Document Relevance from the Clickthrough Logs” by Georges Dupret and Ciya Liao won Best Paper Award. Keynotes were given by Soumen Chakrabarti of IIT Bombay and Susan Athey from Harvard. Chakrabarti described an architecture to annotate Web documents and perform complex reasoning on them using a structured query language. Athey talked about her research during her second-day keynote. Her research focuses on the design of auction-based markets, a topic core to the business of search, which largely relies on auction-based advertising models. User-generated content was a persistent theme throughout the conference. Interestingly, the tweet stream for #wsdm2010 was projected alongside the presentations, providing a unique opportunity for real-time local and remote interaction.