A system for selecting a candidate advertisement for linking to a web page based on the content of the web page. The content of the web page may be automatically determined and then compared to content of the candidate advertisement to determine which candidate advertisement to select. The system can be used to implement a structured advertising system for the World Wide Web. Web pages are searched and indexed, producing indexed content data. This indexed content data is then ranked according to relevancy. The ranked content data are compared to content data of advertisements and an advertisement is selected. The advertisement is then copied onto (linked to) the Web page. Other embodiments may be described and claimed.