Towards Understanding Complex Known-Item Requests on Reddit

Given the important role of search engines in our everyday lives, a better understanding of the information needs that guide our information seeking behavior is essential. Known-item needs form a particular type of information need and occur when a user has a limited but concrete description of an existing object and would like to (re-)find it. Most studies of know-item needs have focused on the short query representations of these needs as they occur in search engine logs. In this article, we focus on richer, more complex known-item need representations posted to six dedicated Reddit discussion forums in the casual leisure domain. An analysis of 462 known-item requests from these subreddits revealed 33 different relevance aspects of items in a variety of different domains. Some of these aspects are highly domain-specific, while others are broadly applicable across domains. The domain %of the item sought also has a strong influence on the length of the known-item requests. Our findings can be used to prioritize efforts to help existing search engines better support known-item needs, both by highlighting which aspects are easier to classify automatically and by determining which information sources should be added to a search engine's index.