Advertisers are permitted to put targeted ads on, or to serve ads in
association with, various content such as search results pages, Web
pages, e-mail, etc., without requiring the advertiser to enter and/or
maintain certain targeting information, such as keyword targeting. This
may be accomplished by using a searchable data structure, such as an
inverted index for example, of available advertiser Web information. The
advertiser Web information may include terms and/or phrase extracted from
the advertiser's Website. In particular, a search query may be used to
search for matching advertisers, and therefore matching ads. For example,
the search query can be used to search an inverted index including words
and/or phrases extracted from advertiser Websites. The advertiser Web
page, or some other identifier, can be used as a key to search for an
associated ad.