This course will introduce the students to various challenges and opportunities in rapidly growing community-based question-answering (CQA), with emphasis on content quality and ranking, as well as usage and user satisfaction. Question answering helps one go beyond traditional keywords-based querying and retrieve information in more precise form than given by a document or a list of documents. Several CQA services have emerged in the recent years allowing information seekers pose their information need as questions and receive answers from their fellow users. This has created new challenges for IR researchers relating to content ranking and evaluation within and outside a CQA site. The social/community aspect of IR is unique and important to address in the swiftly changing landscape of the Web.The course will cover (1) understanding structures and functionalities of a CQA service from a developer's view, (2) criteria relating to motivations and satisfaction from a user's view, and (3) methodology for collecting and analyzing CQA data from a researcher's view. In particular, the course will teach a student tools and techniques for obtaining data from various CQA sites, extracting textual and non-textual features from this content, and using them to rank and evaluate for its usefulness and relevance.