17. A method for selecting advertising for display with a web page requested by a user comprising: receiving, as input, a plurality of documents and a plurality of key terms; analyzing content of the plurality of documents; automatically generating a key term feature vector for each key term based on the content of the plurality of documents, each key term feature vector comprising elements comprising a plurality of words or phrases that are related to the corresponding key term; analyzing at least one of a Universal Resource Locator (“URL”) of said web page and a content of said web page; automatically generating a document feature vector based on the URL or the content of the web page, the document feature vector comprising elements comprising a plurality of words or phrases that are contained in the URL or content of the web page; comparing the key term feature vector and the document feature vector; generating a relevance factor based on the similarity of the elements of the key term feature vector and the document feature vector; and providing a relevant advertisement for display by said web browser with said web page according to the determined relevance factor.
29. The method of claim 17 , further comprising: receiving a plurality of documents from said web browser; and parsing the plurality of documents to generate the key term feature vector of the plurality of documents.