JuniorOptimizer - 10:59 am on Sep 7, 2005 (gmt 0)
This is obviously because of the much larger inventory of advertisers. Most people using AdWords have written very targeted ads for each specific phrase. The YPN inventory is much lower, and therefore displays more general ads, which results in lower CTR. Funny enough, the money is still higher for me in YPN than Google because the EPC is 500% higher. When the targeting gets better, this won't even be close.