More and more search engines are using link popularity as a ranking criterion. It all started with Google, and now other search engines, such as MSN, Inktomi, AltaVista, HotBot, Northern Light, and Excite, also use link popularity in their algorithms.

Your link popularity is based on the sites linking to your pages. The factors determining link popularity are the quality of sites linked to yours, the relevance of those sites to yours, the quality of the link’s text, and in some cases even the number of links (but in most cases it’s quality versus quantity).