(CNN) -- Elmo and Gordon want you to wash your hands so you don't catch the flu.
Smokey Bear, the Ad Council's most famous icon, has moved from 1940s posters to his own Facebook page.
The "Sesame Street" stalwarts star in a series of public service announcements to teach children healthy habits in the face of the H1N1 flu virus.
The Muppet and the man (actor Roscoe Orman) are the latest in a long line of characters -- human and not -- to star in public service announcements co-sponsored by the Advertising Council.
The Ad Council, the charitable arm of the advertising industry, employs the same top-flight talent that creates ads for Budweiser, Coca-Cola and other familiar brands. Watch Elmo and Gordon give the pitch »
Growing beyond its early "Buy War Bonds" posters and Smokey TV spots, today's Advertising Council is moving into social media "in a very big way," said Peggy Conlon, the organization's CEO.
"There's all kinds of ways the Advertising Council finds its target audience on the web," she said, noting that the group has its own YouTube channel.
A marketing executive endorses the approach.
"If your target is young people, television really doesn't make a lot of sense now if they're spending hours on the Internet, hours in social media," said Ben Kunz, director of strategic planning for Mediassociates, a media planning and Internet strategy firm. "You need to find a way to reach them in the media that they consume."
The "holy grail" is to go viral, as people pass the message around because they like it or think it's important, Kunz said. A gory, four-minute British PSA on the dangers of texting while driving has received nearly 600,000 views on YouTube in less than two weeks, fueled in part by Facebook and Twitter links. Watch how the PSA has changed minds »
"If you can leverage these new human networks using mobile and Facebook and Twitter and blogs to disseminate your message, that's the real home run," he said. "But the only way to do that is to give people a real reason to become engaged."
One campaign that tries to do that is called Boost Up, aimed at encouraging students to complete high school.
Louis Caldera, who at the time was secretary of the Army, initiated the project with a call to the Ad Council because of a lack of qualified recruits.
"There was a disconnect between the societal message that said, 'Go to college,' and [the Army's] message, which said, 'Don't go to college, join the military,'" Caldera, a West Point alumnus, told CNN.
Caldera wanted people to think of the Army as a leader in education issues, not an alternative to schooling, and he sought the Ad Council's help.
"We absolutely did not want people to think this was about recruiting," he said.
The council put together a campaign intended for all students, with a particular goal of reaching Latinos, for whom dropout rates are higher than for other groups.
"It really encourages people -- both adults and their peers -- to give these kids the encouragement that they need to really reach within themselves and find the personal resolve that they need to overcome life's difficulties and graduate from high school," Conlon said. "It's a really smart campaign. I think it's very genuine, and it resonates really well with kids."
Although dropout rates generally and among Latinos remain high, "I think this is making a contribution to creating the environment in which more students can be successful," said Caldera, now a senior fellow with the Center for American Progress, a Washington think tank.
President Obama will appear in the latest series of Boost Up PSAs, to begin airing next week.
The Ad Council and its partners measure a campaign's success by how much donated media a campaign attracts. Media outlets will run an ad more if it helps them retain audiences, Conlon said. The Ad Council receives $1.8 billion a year in donated media, she said. Watch some notable Ad Council PSAs »
The council also measures response to phone numbers or Web sites promoted in the ads and tracks awareness through before-and-after surveys, Conlon said.
"We can watch the needle move over time," she said. "It's very scientific; it's very empirical."
But not every campaign is a home run, Conlon admitted.
"We kind of laugh about the Gerald Ford 'Whip Inflation Now' with his big WIN buttons," she said. "The Advertising Council did that campaign, and for many reasons that were mostly cultural, it completely bombed."
And then there are those campaigns that get mixed reviews.
"The 'Just Say No' campaign was probably the biggest success," Kunz said. "I think it led to something like the creation of 5,000 clubs around the country, and there was a definite decline in drug use."
"It was a terrible campaign," she said. "And the reason was not because we shouldn't be telling young people not to use drugs, but it's just not as simple as that. It stripped it down to such a simplistic message that it had terrible reaction on the part of kids."
Campaigns are about educating the public on the facts of an issue, Conlon said.
"You have to get their attention, and that's where the creativity comes in," Conlon said. "It can't be just lecturing or just exposing the message to people. In this cluttered media environment, you really have to have something that breaks through."
One creative spot that has broken through on an emotional level depicts a grown man practicing cheerleading moves on a sidewalk. The humorous ad promotes fathers' involvement in their children's lives.
"Being a good dad sometimes requires shamelessness," said Bill Ludwig, creative director at the Campbell Ewald ad agency in Detroit, Michigan, which created the spot. "The idea is that the smallest moments can have the biggest impact on a child's life. Just spend a little time with your kid."
The father-daughter message touched Facebook user Jessica Gonzales, a graduate student in San Diego, California.
"There's plenty of ads telling us what to buy, how to look, etc., but few remind us how to just be ... and how to be good to one another," Gonzales said. "The ad's tagline is 'Take time to be a dad,' but that message could be easily translated to so many other roles: Take time to be a friend, a mentor, a positive influence."
That's the kind of response the U.S. Department of Health and Human Services is hoping to get from co-sponsoring the "Sesame Street" flu campaign.
"We are doing everything we can to protect public health and teach children how they can stay healthy and safe," said Health and Human Services Secretary Kathleen Sebelius. "Elmo, Gordon, Sesame Workshop and the Ad Council are delivering an important message to our kids."