This is similar to what Tim Ferriss describes in 4-Hour Workweek. He'd create one-page microsites (similar to what Launchrock offers nowadays), buy up proper domains, and then test his product idea by purchasing search engine ads.<p>Not only could he iterate on product idea by tweaking the search ads and reacting to CTR changes, but visitors to the sites were advised to leave their email, so by the time the product was ready to launch, he'd have a great opt-in list.