Yet Another Related Posts Plugin (YARPP) gives you a list of posts and/or pages related to the current entry, introducing the reader to other relevant content on your site.
http://wordpress.org/extend/plugins/yet-another-related-posts-plugin/
Widgets · WordPress Plugins
Get access to data on 486,480 websites that are Yet Another Related Posts Plugin Customers. We know of 139,476 live websites using Yet Another Related Posts Plugin and an additional 347,004 sites that used Yet Another Related Posts Plugin historically and 74,214 websites in the United States.
Get a list of 486,480 websites using Yet Another Related Posts Plugin which includes location information, hosting data, contact details, 139,476 currently live websites and an additional 64,988 domains that redirect to sites in this list. 347,004 sites that used this technology previously and 74,214 websites in the United States currently using Yet Another Related Posts Plugin.