UGC platforms such as Wikipedia, online review platforms, online Question and Answer forums have permeated many economic and societal activities and established their important roles in our lives. However, the secrets of enabling and sustaining the supply of UGC have only received limited attention. Needless to say, without a steady supply of quality content, UGC would not persist. My dissertation focuses on the supply of online reviews/ratings – a dominant source for consumers’ decision making. Volume, valence, and quality of online reviews are inter-related aspects. Accordingly, this dissertation consists of three chapters focusing on the three aspects. The first chapter explores whether friend contribution can be used to motivate users to write more and better reviews. The second chapter examines whether online ratings are robust to rating aberrations such as random ratings and fake ratings. The third chapter develops a measurement for assessing review quality and investigate the relationship of helpfulness votes (a commonly used proxy for review quality) with review quality.