The technology generally relates to automatically associating products and services to be advertised in response to a search query and providing sponsored advertisements for output with the search query results on a publisher's website or mobile application. An ad advertiser may create an ad campaign for products without including or identifying keywords associated with the product. Upon receiving a request for an advertisement, an ad server may generate synonyms, or keywords, for the terms in the request. The ad server generated keywords may be used to identify available products that match, or are relevant to, the search query. The ad server may determine a quality of the match and, based on the quality, determine which products are most relevant to the search query. The ad server may solicit bids from the advertisers of the relevant ad campaigns. The winning ads may be returned to the publisher for output.