  As social Q&A sites gain popularity, it is important to understand how users
judge the authoritativeness of users and content, build reputation, and
identify and promote high quality content. We conducted a study of emerging
social Q&A site Quora. First, we describe user activity on Quora by analyzing
data across 60 question topics and 3917 users. Then we provide a rich
understanding of issues of authority, reputation, and quality from in-depth
interviews with ten Quora users. Our results show that primary sources of
information on Quora are judged authoritative. Also, users judge the reputation
of other users based on their past contributions. Social voting helps users
identify and promote good content but is prone to preferential attachment.
Combining social voting with sophisticated algorithms for ranking content might
enable users to better judge others' reputation and promote high quality
content.
