1. A method in a computer system with a processor and storage device for using a hierarchy showing a web page and child web pages in a web site for generating a feature of the web page, the method comprising: providing the hierarchy of the web pages of the web site, wherein a parent web page of the web site and a child web page of the web site have a parent and child relationship when the parent web page is identified by a parent uniform resource locator of a parent depth and the child web page is identified by a child uniform resource locator of a child depth such that the parent uniform resource locator is a prefix of the child uniform resource location and the child depth is one more than the parent depth irrespective of whether the parent web page has a link to a child web page or whether the child web page has a link to the parent web page; for each of a plurality of topics, calculating relevance of the web page to the topic by: when the web page has no child web page as indicated by the hierarchy, setting the relevance using the web page; and when the web page has a child web page as indicated by the hierarchy, setting the relevance using the web page and the child web page; and for each of a plurality of features, when the web page has no child web pages as indicated by the hierarchy, setting the feature of the web page using the web page; when the web page has a child web page as indicated by the hierarchy, setting the feature of the web page using the web page and using the child web pages.