9. A system, comprising: a processor; and storage coupled to said processor and containing software that, when executed by the processor, causes the processor to run a plurality of classifiers on a web page to obtain one or more keywords and to select advertisements based on said one or more keywords, each classifier being previously determined based on positive and negative training examples.
9. A system, comprising: a processor; and storage coupled to said processor and containing software that, when executed by the processor, causes the processor to run a plurality of classifiers on a web page to obtain one or more keywords and to select advertisements based on said one or more keywords, each classifier being previously determined based on positive and negative training examples. 13. The system of claim 9 wherein the processor further causes the advertisements or a link to the advertisements to be included with the web page.