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 470,096 websites that are Yet Another Related Posts Plugin Customers. We know of 148,064 live websites using Yet Another Related Posts Plugin and an additional 322,032 sites that used Yet Another Related Posts Plugin historically and 78,308 websites in the United States.
Get a list of 470,096 websites using Yet Another Related Posts Plugin which includes location information, hosting data, contact details, 148,064 currently live websites and an additional 67,475 domains that redirect to sites in this list. 322,032 sites that used this technology previously and 78,308 websites in the United States currently using Yet Another Related Posts Plugin.