You see them so often, you feel like you know them. But they're not ordinary TV characters. They're the familiar faces in commercials.

"There's a long history of people who became famous through advertising," said Advertising Age writer Ira Teinowitz. "You pick up people who were nobodies before and became somebody through media advertising."

Among the most recognizable ad stars of today is "Steve, the Dell computer guy"  actor Ben Curtis, who makes the company's sales pitch by playing roles varying from graduation speaker to shopping mall employee. And there's the Ditech.com character, actor Ron Michaelson, who consults a magic 8-ball in one spot for the online mortgage company and dresses in drag to play his mother in another.

And who can forget Clara Peller, the star of the Wendy's commercials who made the phrase "Where's the beef?" part of contemporary American lingo?

While these actors are familiar to audiences, commercial stardom can be both a blessing and a curse.

Though industry insiders say actors have to choose their commercial work carefully, they agree that starring in ads is more likely to help an acting career than hurt it.

"So many start off in commercials and segue into TV and movies," said Brooke Slavik, a talent agent at The William Morris Agency in Los Angeles. "Certain commercials can elevate a career and heighten awareness of an actor."

Actress Barbara Feldon, who played Agent 99 on the 1960s sitcom Get Smart, catapulted to fame after she appeared in a commercial for Top Brass Hair Dressing for Men. Orlando Jones was the pitchman for 7-Up before he went on to high-profile movie roles like those in Evolution and Double Take. And David Leisure, who played Joe Izuzu in the car company's spots, got cast in television shows like Empty Nest thanks to his commercial work.

"You can have problems with typecasting," Teinowitz said of commercial acting. "But you get a certain recognition factor."

Michaelson, the face of Ditech.com, has done about 300 commercials in his 20- year career  and landed small roles on shows like The Golden Girls, Making a Living, Moonlighting, and Jack and Jill.

"Theatrically, it's only a positive," Michaelson said of commercial work. "If it's a character who seems to capture the imagination or someone the public likes, then they'll want to see more of you."

But having a recurrent role in an ad can make it difficult for an actor to be cast in other commercials, according to Michaelson.

"Advertisers tend to shy away from someone too well-known for a particular product only because it wouldn't sell their product," he said.

And there are other risks associated with doing commercials. If the spot winds up being a bust, it can mar an actor's reputation, Slavik said.

"If the product isn't great or the creative elements of the commercial aren't great, it can hinder your career," she said.

For advertisers, creating an appealing commercial character and casting a good actor to play the part is almost always a smart move.

"Anything you can do to quickly identify your brand is good for you," said Teinowitz. "If you can get a recognizable face or character that immediately translates into identifying your brand, then you can spend the time selling the product as opposed to identifying the brand."

The danger, ironically, is that the ad or actor will dazzle audiences too much, causing them to lose sight of the brand being sold.

"The entertainment value or the actor can overshadow the product," Teinowitz said.

He remembers that happening with the "less filling, tastes great" Miller Lite beer campaign.

"People started to look for entertainment without paying attention to the product," he said. "They forgot the name of the beer."

But although most commercial actors are hoping for their big TV or film break, many never get it and become seasoned ad stars instead.

"We're kind of anonymous," Michaelson said. "We're the blue-collar workers, the ones you just don't notice."