Page Yield

This is the percentage of unique pages that yield search-delivered traffic in a given month.

This ratio essentially is a key driver of the length of your “long tail” of natural search. The more pages that yield traffic from search engines, the healthier your SEO program. If you have only a small portion of your website delivering searchers to your door, then most of your pages, your virtual salespeople, are warming the bench instead of working hard for you. My colleague Brian Klais has a name for the webpages that aren't driving any search traffic — freeloaders.