Google is still in the early stages of dabbling in TV advertising, but the search giant is already rolling out a new feature to see how effective those TV ads are.

A new Google Analytics feature lets advertisers examine website metrics side by side with metrics from TV ad campaigns, essentially allowing advertisers to see if TV commercials drive web traffic.

Analytics already allows webmasters to measure visits, conversion rates and revenue, and will now offer those same metrics alongside TV metrics like impressions delivered, number of ad plays, cost and CPM paid, according to Google's AdWords blog. Google TV ads currently appear only on the Dish satellite network.

The side-by-side comparison may be the first step toward Google Analytics becoming an essential marketing tool. TechCrunch blogger Erick Schonfeld sees the potential for Google to go further by adding radio, print and other forms of advertising.

"If advertisers can truly get to the point where they can measure all of their ad campaigns across all media in one place, then they will shift those advertising dollars to the most efficient place. And that may not be the web in all cases," Schonfeld wrote.