Google, Yahoo, others work to make search engines better at scanning the Web

The first search engines presented pages in the order they were found. Once searches started turning up thousands of matches, that approach was of no use, since the best match may have been buried in pages of junk. The next generation incorporated the idea of a search algorithm, a method to evaluate how well a page matched the query. Results were scored based on whether the search terms were included in the title, how high on the page they appeared, and whether they were capitalized or bolded.

Read more.