Since the term was coined in 2005, Web Science has provided a rallying call for researchers who are interested in the social and organisational behaviour engendered by the Web as about the underpinning technology. Web Science is inherently inter-disciplinary. Web Science research aims to provide the means to better model the Web’s structure, describe the principles that have fuelled its phenomenal growth, and discover how online human interactions are driven by and can change social conventions. Research is needed to reveal the principles that will ensure that the network continues to grow productively. Research is required to implement principles that can settle complex issues such as privacy protection and intellectual property rights. Of course, we cannot predict what this nascent discipline might reveal. But Web science has already generated powerful insights, how the Web is structured, how resilient it is, how ideas travel through the tens of millions of blogs, how we might include information in Web content so that its accuracy and origin is more transparent. At the micro scale, the Web is an infrastructure of artificial languages and protocols; it is a piece of engineering. However, it is fundamentally about the interaction of human beings creating, linking and consuming information. It is this interaction that we also need to research and understand. It is this interaction that generates the Web's behavior as emergent properties at the macro scale. These macro properties are often surprising and require analytic methods to understand them. The Web’s use is part of a wider system of human interaction – the Web has had profound effects on society, with each emerging wave creating both new challenges and new opportunities available to wider sectors of the population than ever before. The Web Science Research Initiative (WSRI) was launched in November 2006 by Tim Berners-Lee, Wendy Hall, Nigel Shadbolt and Daniel Weitzner. At WWW2007 in Banff, WSRI sponsored a reception to present the ideas behind Web Science to the WWW community. At WWW2008, WSRI sponsored a workshop entitled “Understanding Web Evolution: A Prerequisite for Web Science” chaired by Dave De Roure. It attracted a lot of excellent papers – see http://webscience.org/events/www2008/ - and was one of the largest workshops at the conference. In March 2009, WSRI is running its first Web Science conference in Athens, WebSci’09 – see www.websci09.org - with the aim of bringing computer scientists and social scientists together to discuss this important topic. The aim of this panel is to bring this debate to the heart of the WWW community at WWW2009 in Madrid.

Ricardo Baeza-Yates @VideoLectures.net