Cell phone and media companies expect mobile advertising to soon become a sizable market and will offer, inter alia, ad-subsidized mobile video services, according to top executives at the Reuters Global Technology, Media and Telecoms Summit, Reuters reports. Viacom is working with major operators and planning mobile ad trials; Sprint wants to offer subsidized wireless video and local ads on phones.

"The whole advertising world has a new mechanism to reach their customers. You can hone in on customers in your area," said Sprint Nextel Chief Technology Officer Barry West. Sprint could also offer cheaper mobile video services if ads are included.

"It's a major opportunity," Martin Sorrell, chief executive of WPP Group, said at the summit, adding that the potential of measurability was a key attraction of mobile advertising - and it would become mainstream "quickly."