Today, that 30-second spot is quaint

In the 1960s Madison Avenue era, painstakingly re-created in the cult hit television show "Mad Men," advertisers could buy a fixed block of airtime on television and be guaranteed a captive audience. That's what Winston cigarettes did for the inaugural season of "The Flintstones" in 1960: Cartoon-loving prospective smokers tuned in to see Fred and Barney gleefully puffing away, shilling the product.

Now, if we don't like an ad, we can zap it into consumer oblivion. If we discover it is untruthful, we can trash the brand on our blogs or write nasty comments on YouTube.

But if we're entertained enough by something a brand does, we can do its job for it -- by becoming its social media champion. That's what millions of people do every day. They "elf" themselves for OfficeMax each holiday, spreading the word about discount paper products while having online fun in Santa's workshop. They had their way with a man in a chicken suit in Burger King's "subservient chicken," which had 25 million visitors during its first 48 hours online.

And recently hundreds of thousands were playing along with AMC's ramp-up for "Mad Men's" third-season premiere Sunday, joining a "Mad Men Casting Call" and flocking to the meta social-media promotion "Mad Men Yourself," which lets people swap their Facebook profile pics for hip "Mad Men" avatars.

Ads in the "Mad Men" day were about the art of persuasion. Advertising today is about the art of engagement.

Instead, I saw discreetly branded viral video shorts, graphic novels and performance art. I saw Facebook and Twitter campaigns for mega-brands, real-world scavenger hunts and online interaction with fictional characters. (When I left advertising in 2005, every major campaign still revolved around the almighty TV spot.)

While we can now assert more control over advertising, we're unwillingly being bombarded by more messages than ever, infiltrating our lives in new, increasingly insidious ways.

The market research firm Yankelovich estimates that the average American living in a city 30 years ago saw up to 2,000 ad messages a day. Today, estimates range from 5,000 to 20,000 ad impressions a day. To get a more accurate number, one would have to determine what exactly constitutes an ad in today's ambiguous media environment. What about Internet search results, recommendations on Amazon, subtle product placements in film, music and TV, and spam?

Then there's the blogosphere, where an entire cottage industry blurs the line between content and advertising, truth and spin.

This month, it was revealed that pharmaceutical companies had hired ghostwriters with no medical training to produce and disseminate "research papers" for online public consumption. Before that were the mommy bloggers: parents writing about their children and their children's favorite products.

The Federal Trade Commission has proposed that all bloggers, and the corporations that sponsor them, be held accountable for their claims' validity. It is updating its guidelines on endorsements and testimonials for first time since 1980. Good luck with policing the entire digital universe.

In 50 years we've gone from loosely regulated advertising based on the art of persuasion, to more regulated, perfectly legal and often spectacular ads based on the art of engagement, to anything goes.

Which brings us back to 1962 and Don Draper. Would his contemporary self approve of mommy bloggers and pharma spam? Or would he evolve and become a proponent of ethical, engaging ads?

For an answer, look to Season One, Episode Six, when a beatnik says to Draper: "You work in advertising. ... How do you sleep at night?"

The Mad Man's response: "On a bed made of money."

James P. Othmer, a former advertising executive, is author of the upcoming book "Adland: Searching for the Meaning of Life on a Branded Planet." He wrote this article for the Washington Post.