It seems Google is establishing a beach-head into yet another area, and a juicy one as far marketing is concerned: TV advertising. No longer content with the online ads built in to its search engine, Google have signed a contract with NBC Universal, a subsidiary of General Electric, to sell ads through NBC’s television channels.

In the advertising industry, time allocated for commercials is called Inventory. Although NBC’s Inventory was mostly booked during a period of increased ad sales last spring, some leftovers are there (called “scatter advertising”), in which NBC will allow Google to sell TV ad space to its clients. While the space is relatively small, keep in mind that NBC’s yearly generated ad revenue is around $6 billion.

Google have had some experience with TV advertising in the past, through a partnership with EchoStar DISH, a national satellite network; this is a step up though, as NBC marks as much as 1.7 million viewers on the Sci-Fi channel alone during prime time, and it is one of several of NBC’s channels through which Google will advertise.

Google believe they have found a market in small-to-medium size companies who have advertised online before, yet are still uncomfortable or inexperienced with TV ads. In return, not only will NBC get a share of the ad revenue, but Google promise to use the experience from DISH, as well as a new system similar to their online AdSense, to better target ads at specific consumers, and tell whether a particular commercial does well or poorly by using a system that offers second-to-second updates in the number of viewers.