“What all marketers are dealing with is an absolute sensory overload,” said Gretchen Hofmann, executive vice president of marketing and sales at Universal Orlando Resort. The landscape is “overly saturated” as companies press harder to make their products stand out, she said.

Outright advertising is just one contributing factor. The feeling of ubiquity may also be fueled by spam e-mail messages and the increasing use of name-brand items in TV shows and movies, a trend known as product placement. Plus, companies are finding new ways to offer free services to people who agree to view their ads, particularly on the Internet or on cellphones.

More is on the horizon. Old-fashioned billboards are being converted to digital screens, which are considered the next big thing. They allow advertisers to change messages frequently from remote computers, timing their pitches to sales events or the hour of the day. People can expect to see more of them not only along highways, but also in stores, gyms, doctors’ offices and on the sides of buildings, marketing executives say.

The trend may lead to more showdowns as civic pride is affronted. “They’re making our community look like Las Vegas,” said Barbara Thomason, president of the Houston Northwest Chamber of Commerce, of the scores of digital signs she has noticed popping up in the last few years. “The word ‘trashy’ has been used.”

Some advertising executives say that as long as an advertisement is entertaining, people do not necessarily mind the intrusion — and may even welcome it.

In some office buildings, for instance, video screens in elevators provide news and information as well as ads. This year video screens will be placed in about 5,000 New York City taxicabs, where passengers will see both advertisements and NBC programs, according to Clear Channel Outdoor, which is installing the screens.

Image An ad for the Florida Lottery on the floor of a sports arena in Orlando, Fla. The jackpot is updated automatically.

“If you do it the right way, you actually win points,” said John McNeil, executive creative director at McCann Worldgroup San Francisco. His agency designed ads for Microsoft that appeared on tray tables in US Airways planes last spring.