I appreciate your opinion. But I don't believe that "yellow page" is a trademarked term. There are numerous sites out there with yellow in it i.e. yellowpagecity.com, b2byellowpages.com, trueyellow.com, internetyellowpages.com, yellowpagesinc.com
along with a few recent sales
ottawayellowpages.com for $2705 @ snapnames
edmontonyellowpages.com $2900 @ snapnames
So don't you think yellowad (dot) com should be good?
Also here is some stats from adwords kw tool
yellow ad $4.50 apc with 8,100 average local searches