Some owners of content sites are earning four and even five-figure incomes per month selling "nothing." They're doing this by selling their targeted traffic to other websites through Google's AdSense program.

If you're not familiar with (r)AdSense, it's where (r)Google pays website owners ("publishers") to run ads on their sites. Google accepts paid ads from advertisers, and then shares this revenue with the publishers who allow these ads to be displayed on their...