CNN/Money (NEW YORK) - The U.S. advertising market is looking increasingly like a tale of two cities.

Almost midway through 2005, Internet and cable television advertising is strong, while network television and newspapers are struggling. The verdict on radio and magazines: ho-hum.

Taken together, Merrill Lynch analyst Lauren Rich Fine concluded in a report released Friday that there is "absolutely no momentum" in U.S. advertising.

The bland picture could explain why shares in leading media companies, which count on advertising for their lifeblood, are down this year. Shares in Time Warner (unchanged at $17.57, Research), Viacom (down $0.20 to $35.00, Research) and Clear Channel Communications (down $0.28 to $29.86, Research) have fallen year-to-date. Newspaper stocks, including The New York Times Co (down $0.02 to $31.62, Research), Tribune Co. (unchanged at $36.44, Research), and Gannett Co. (up $0.02 to $75.04, Research), have been especially hard hit.

Time Warner is the corporate parent of CNN/Money.

Meanwhile, investor enthusiasm for Internet search giant Google (up $2.55 to $261.75, Research) shows no signs of abating. Goldman Sachs predicted this week that online ad spending will grow 28 percent, to $12.3 billion, in 2005. Google is the top player in "paid search" advertising, one of the most popular forms on online advertising in which ads appear next to Internet search results but advertisers pay only when users click on those links.

Google competitor Yahoo! Inc. is also benefiting from the online ad boom, although shares in Yahoo! (up $0.25 to $37.39, Research) are down more than 1 percent this year.

"Online gains are coming from both increased incremental spending by advertisers and at traditional media's expense," Merrill Lynch's Fine wrote in her report.

The report comes as the major television broadcast networks are trying to sell commercial time for the fall season. Merrill Lynch and other media analyst predict advance sales of primetime advertising will be flat at about $9.1 billion or slightly higher this year compared to a year ago.

Cable network sales, on the other hand, are expected to grow 11 percent, to $7.3 billion, due to climbing ratings and lower ad rates compared to network television.