What's the difference between a Recommended and Certified Installer, Member Installer and Courtesy listings?

Recommended Installers Network offers enhanced listings to advertisers that may include graphics, links and other functionalities. When you perform a search, the Recommended and Certified Installer listings appear at the top of the results page, over Member and Courtesy listings. Member Home Theater Installer listings are given priority placement over Courtesy listings. Courtesy Home Theater text listings are listed below, in alphabetical order. ... more