1. A method comprising: determining a strength of a correspondence between a search query and a title of a listing of an item on a network-based publication system, the search query including a keyword, the determining of the strength of correspondence based on an analysis of a set of actions previously taken by a set of users after submitting a set of previous search queries including the keyword; generating a set of annotations corresponding to the search query, the generating including identifying a type of the item and a confidence measure pertaining to the identifying of the type of the item; propagating the set of annotations to a search engine for use in enhancing search results generated by the search engine; and presenting the enhanced search results generated by the search engine, the enhanced search results including a filtering of the search results based on the type of the item and the confidence measure.