From the May 6 NYT story:
... While short, multiepisode cellphone series are growing in popularity, the lucrative advertising dollars prevalent in other entertainment segments — and which studios rely on for profit — have been slow to migrate to the supersmall screen. ...
In the two years since Fox Mobile and MTV Networks pioneered the market for cellphone programming, almost every major film and television studio is developing projects. But, for now, advertisers are reluctant to abandon traditional formats.
In 2006, $421 million was spent on mobile phone advertising, said a study by the market research firm eMarketer. By contrast, broadcast television advertising was estimated at $48 billion last year, according to the Universal McCann media agency.
“If you think about what the market could be from an advertising perspective, it is a dream,” said Linda Barrabee, an analyst for wireless mobile communications at the Yankee Group, a research firm in Boston.
“That’s why you see a lot of companies playing with different concepts and ideas,” she said, but added that “it’s hard to target advertising in a meaningful way. From a brand perspective, they haven’t figured it out.”