http://www.pcworld.com/news/article/0,aid,123705,00.asp
New Model, New Profits
The acknowledgment by search giants Google and Yahoo that they are
dipping their toes into pay-per-call is significant news for the new
online ad model, said Greg Sterling, a Kelsey Group analyst. It is also
good news for companies that would rather generate calls than Web site
clicks from their online ads, Sterling said.
If Google were to fully embrace pay-per-call, the benefits would include
getting a higher revenue rate than from pay-per-click, because
pay-per-call ads in general tend to be more expensive, he said.
Typically they start at around $2 per call, average about $7, and can
cost more than $30, Sterling said.
Advertisers are generally willing to pay more for a call than for a
click because a prospective client who calls is presumably closer to
making a buying decision than one who visits a Web site, he said.