A tool released by Google will tell advertisers which Wwebsites their ideal customers are inclined to visit.

Dubbed the "Google Ad Planner," it lets advertisers enter demographics they wish to target and then returns a list of Websites likely to appeal to people with those characteristics. It is still in the private test phase, but it could lead to more popular sites getting more popular.  If advertisers pay attention to it, it could mean that newer sites are ignored as too risky.

The announcement comes a week after the launch of a "Google Trends for Websites" feature that lets people rank the popularity of Websites that interest them.