MediaBuyerPlanner: Video on demand - which allows viewers to choose what program they want to watch when they want to watch it - has been around for years, but until now the growth of advertising within the medium has been slow. The best programming generally charged a fee to viewers, who would not likely be open to watching ads on top of that. Plus, of course, fast-forwarding through ads is par for the course for viewers.

But now, free video on demand has been expanding as cable operators create new services to battle satellite, and advertisers have begun to climb aboard, writes The Wall Street Journal. For example, Kraft Macaroni & Cheese is sponsoring a show called Katie Brown @ Home, along with four other programs on the on-demand Rainbow Media network owned by Cablevision systems. Each show begins with a 15- or 30-second spot from Kraft and includes integrated ads during the show, such as pop-up cooking tips.

Five years ago, about two-thirds of Kraft's total ad budget was used for broadcast TV. Now, two-thirds is devoted to a mix of media, including print, cable, online, in-store and video on demand. Car companies, too, are embracing video on demand, because it offers the ability to give car-buyers, always hungry for information, the details they're looking for.

Measurement companies Nielsen Media Research and Rentrak are developing methods to track what is being watched, by whom and for how long.