The sites with most text matches rank highest on the list of results. This method is a good start, but it often turns up long lists of obscure and inappropriate sites. Some sites manipulate this system by invisibly writing one word hundreds of times on a page to get higher play in the search results. So other methods were developed. The sites with the most links pointing to it are most likely to be read, making it more likely to be relevant to the average user.
Human editors scan Web sites, throw out useless ones and categorize others by subject.
This guarantees you won't come across gross errors, such as finding the history of Turkey under Thanksgiving recipes. But because this indexing is done by hand, the directories don't have the breadth and reach of automated search engines. Still, as anyone who has tried to do a Web search knows, none of the existing techniques is always accurate. One way to make a search more accurate is to personalize the search for each user. The service also organizes results based on the popularity of previous search results.