Web retrieval: the role of users

Web retrieval methods have evolved through three major steps in the last decade or so. They started from standard document-centric IR in the early days of the Web, then made a major step forward by leveraging the structure of the Web, using link analysis techniques in both crawling and ranking challenges. A more recent, no less important but maybe more discrete step forward, has been to enter the user in this equation in two ways: (1) Implicitly, through the analysis of usage data captured by query logs, and session and click information in general; the goal here being to improve ranking as well as to measure user's happiness and engagement; (2) Explicitly, by offering novel interactive features; the goal here being to better answer users' needs. This half day tutorial covers the user-related challenges associated with the implicit and explicit role of users in Web retrieval. More specifically, we review and discuss challenges associated with: (1) Usage data analysis and metrics - It is critical to monitor how users take advantage and interact with Web retrieval systems, as this implicit relevant feedback aggregated at a large scale, can provide insights on users' underlying intent as well as approximate quite accurately the level of success of a given feature. Here we have to consider not only clicks statistics, the sequences of queries, the time spent in a page, the number of actions per session, etc. This is the focus of the first part of the tutorial.

(2) User interaction - Given the intrinsic problems posed by the Web, the key challenge for the user is to conceive a good query to be submitted to the search system, one that leads to a manageable and relevant answer. The retrieval system must assist users during two key stages of interaction: efore the query is fully expressed and after the results are returned. After quite some stagnation on the front-end of Web retrieval, we have seen numerous novel interactive features appear in the last 3 to 4 years, as the leading commercial search engines seem to compete for users' attention. The second part of the tutorial will be dedicated to explicit user interaction. We will introduce novel material (as compared to previous versions of this tutorial that were given at SIGIR'2010, WSDM'2011 and ECIR'2011) in order to reflect recent Web search features such as Google Instant or Yahoo! Direct Search.

The goal of this tutorial is to teach the key principles and technologies behind the activities and challenges briefly outlined above, bring new understanding and insights to the attendees, and hopefully foster future research. A previous version of this tutorial was offered at the ACM SIGIR'2010, WSDM'2011 and ECIR'2011.