Pure Play Facebook Sites
These are purely facebook sites, meaning they don't have other content associated with them nor are they part of a larger site.
The Yell Facebook application has some of the best production values of any YP's Facebook applications. Still, has some usability challenges.
YPG's Facebook application clean and straight-forward. Built around search and creating lists.
Mixed Play Sites featuring Facebook
These are the facebook sections or "features" of another, larger site. These sections compete with the Pure Play sites.
Yellow Pages Canada helps people distribute listings to their Facebook profile.
The Yell Facebook application (called Socializer) has some good production values. Good home page with a 1-2-3 help and a simple proposition to "find ideas" to "inspire me."