WICOW 2009 was organized in conjunction with the 18th International World Wide Web Conference in Madrid, Spain on April 20, 2009.
As computers and computer networks become more common, a huge amount of information, such as that found in Web documents, has been accumulated and circulated. Such information gives many people a framework for organizing their private and professional lives. However, in general, the quality control of Web content is insufficient due to low publishing barriers. In result there is a lot of mistaken or unreliable information on the Web that can have detrimental effects on users. This situation calls for technology that would facilitate judging the trustworthiness of content and the quality and accuracy of the information that users encounter on the Web. Such technology should be able to handle a wide range of tasks: extracting credible information related to a given topic, organizing this information, detecting its provenance, clarifying background, facts, and other related opinions and the distribution of them, and so on. The problem of Web information reliability and Web data quality has become also apparent in the view of the recent emergence of many popular Web 2.0 applications, the growth of the so-called Deep Web and the ubiquity of Internet advertising.