Welcome Message

On behalf of the Organizing Committee, I would like to extend a warm welcome to the Fourth ACM International Conference on Web Search and Data Mining (WSDM2011), Hong Kong.

Following the great successes of WSDM2008 in Stanford University, USA, WSDM2009 in Barce- lona, Spain, and WSDM2010 in New York, USA, WSDM2011, Hong Kong has been chosen as the premier annual international ACM conference for presenting the very best research innovations and other significant work covering areas in search and data mining on the Web and the Social Web, with an emphasis on practical but principled novel models of search, retrieval and data mining, algorithm design and analysis, economics implications, and in-depth experimental analysis of accuracy and performance. The purpose and goal of WSDM2011 is to provide a forum for researchers, practitioners, and professionals alike to identify challenging issues in the areas, to share the latest ideas and results, to shape research directions, and to inspire future breakthroughs.

As in the past WSDM conferences, WSDM2011 features top-quality and excellent technical program from a record number of submissions. In particular, WSDM2011's emphasis this year is on Social Computing and related topics. Moreover, here are some of the highlights of the program we have planned at WSDM2011:

• Focused single-track session
• All accepted papers will be full-length with poster-presentations to increase interaction
• A small set of selected oral presentations in concentrated areas
• Two excellent keynote speakers
• Outstanding pre-conference workshops and tutorials

To put together a conference is not an easy task. I would like to thank all the members of the Conference Committee for their dedication and hard work in ensuring an excellent technical program with social activities. In particular, I would like to thank our Program Co-Chairs, Wolfgang Nejdl and Hang Li, the 19 Senior PC members, the 134 PC members, the Best Paper Award Committee, and other reviewers for their great efforts in providing WSDM2011 with an excellent technical program. Last, but not least, I thank all the authors of submitted papers for their contributions and all the delegates for their participation.

My most sincere thanks go to the following Organizing Committee members for their dedication and support in making WSDM2011 a great success: Workshop Co-Chairs, Evgeniy Gabrilovich and Wai Lam; Tutorial Co-Chairs, Marc Najork and Qing Li; Finance Chair, Michael R. Lyu; Publicity Chair, Qiang Yang; Registration Chair, Michael Chau; Publication Chair, Hong Cheng; Local Arrangement Co-Chairs, Dan Hong and Tak-Lam Wong; Poster Session Chair, Jie Tang; Event Coordinator, Samuel Tam; Secretariat, Baichuan Li and Yi Zhu. Without their selfless support, this conference could not have been a success!

I am deeply grateful to our two distinguished speakers Christos Falousos and Harry Shum for their insightful keynote talks that highlight the current research work in web search and mining.

I would also like to thank the sponsors of WSDM2011: ACM, SIGIR, SIGKDD, SIGMOD, SIGWEB, the K.C. Wong Education Foundation, Microsoft, Google, Yahoo, and Yandex. Moreover, we are also grateful to Arnetminer and VeriGuide for their technical assistance. Our special thanks go to Microsoft and Google for sponsoring the Best Paper Award and the Best Student Paper Award, respectively. In addition, Google once again sponsored the Conference Travel Award for Women this year. Their generous sponsorship and support contributed immensely to the success of the conference.

Finally, I thank the WSDM Steering Committee for their vote of confidence to hold WSDM2011 in Hong Kong, and for their guidance throughout the planning and organizing of the conference.

Hong Kong is a world-class metropolis full of dynamism and character. Aside from the technical and social program at the conference, I invite you to take some time to explore the Pearl of Orient and its nearby regions. With the celebration of the Chinese Lunar New Year just before the conference, there are a number of festive events specially prepared to show off the ancient tradition in this modern city. I hope you will have a chance to enjoy it as much as I do.

Once again, I welcome you to WSDM2011, and wish you a very stimulating, productive, and fruitful experience in Hong Kong!

Irwin King
General Chair, WSDM2011
The Chinese University of Hong Kong