Abstract: 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 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. In this tutorial, we will cover the user-related challenges associated with the implicit and explicit role of users in Web retrieval. We will review and discuss challenges associated with two types of activities, namely: usage data analysis and metrics and user interaction. 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.