Jay Weintraub has written a great post on the economics of lead generation. The key take-away is that the prices of leads will increase overtime as the lead market matures.
I will make one conjecture about the tail Jay writes about. The tail is made up of people who aren’t in the mode of becoming a lead yet or not interested in the services you are marketing. The trick will be how we identify those people who aren’t in the mode of becoming a lead yet or will go offline to find their goods or services. The continual advancement of targeting will eventually help in this effort. Using behavioral targeting as an example, if we can identify people who are starting to research mortgages and capture them as a lead online instead of them going offline for their transaction.
As Jay mentions oil extraction is similar to online lead generation, we need tools to extract offline leads from the tar sands of the Internet.