How Do Search Engines List and Rank Content?

That depends on the search engine in question. Each search engine and directory has its own set of Web page ranking and listing criteria. Generally, search engines utilize proprietary ranking algorithms to determine the relevance and hence the ranking of a visited page. When deciding site rankings, search engines focus on such Web page elements as page copy, Title tags, keyword usage, and the relevance of inbound hyperlinks. The latter issue is a particularly prominent element of Google's ranking algorithm. Most search engines use spider technology to collect the listings for their indices. Web directories generally rely on human editors, and page inclusion and ranking decisions are in the hands of those editors. The editors decide if a suggested URL will be included in the directory, and if so, in which category and subcategory it will reside. Most directories present their listings alphabetically.