This is a big problem for traditional news outlets, including broadcast and cable TV, according to a new study from the Pew Research Center’s Project for Excellence in Journalism. Advertising dollars are moving so quickly to the Web that by 2016 it could be the single biggest platform for selling goods and services. But news organizations have done a lousy job of persuading their advertisers to follow them online. For example, it’s hard to watch a network TV newscast without seeing a promo for a prescription or over-the-counter medication; they’re collectively the largest category with 16% of the ads. But they’re harder to find if you turn to the newscasts’ Web sites: Financial services dominate that world with 31.3% of the online ads vs about 8% for the medicines. There’s a similar story in cable news: For example, CNN gets most of its advertising from motion pictures and TV, insurance, and telecommunications. On CNN.com, though, the top categories are financial, toiletries and cosmetics, and job search.

The newscasters bear some of the blame. Most rely on static banner ads and sponsored links. Despite their roots in video, the TV newscasters sell few video ads: they accounted for just 2.5% of cable news’ online ads and much less than that for the network TV sites. If the pattern persists then it “throws into question the financial future of journalism as audiences continue to migrate online,” Pew says.