1. A computer-implemented method of identifying search results based on entity-based knowledge, the method comprising: enumerating one or more entities that may match entities in a search query that includes at least one entity; identifying, as a potential target of the search query, one or more potentially matching entities from the enumerated entities; ranking the identified potentially matching entities so as to distinguish a relative level of match between each identified potential target and the entities included in the search query; selecting one or more of the identified potentially matching entities as matching entities for an entity-based search; performing an entity-based search that narrows results by applying one or more of top ranked, selected ones of the identified potentially matching entities; ranking results to yield results ordered by relevance to the search query, by (i) identifying a first group of one or more results each without an entity identifier; (ii) identifying a second group of one or more results, different from the first group, each with an entity identifier; and (iii) comparing members of the first group with members of the second group, and then (iv) grouping results by entities with which the results are associated.