“…Knowledge of the query's context, which can be a function of the user's knowledge about the domain, previous search queries, etc., is a crucial factor when suggesting terms that help a user find specific information faster. The two main resources available for query recommendation are the document collection (including anchor logs) [28,24,10,18,20,13] and search logs [3,19,12,4,17,6,5,7,8], which can also be used as forms of implicit or explicit feedback to re-rank retrieved documents.…”