What of the Internet? The military was busy building computer networks as far back as the 1960s, and by 1983 a university network was up and running. But the first indication that Discover readers might be so bold as to contact each other electronically came in 1984, when CompuServe advertised its "Personal Communications Network for Every Computer Owner." Using its Electronic Mail system ("we call it Email™"), CompuServe subscribers could deliver "any number of messages to other users anywhere in North America." In the ad, a pajama-clad couple in a tchotchke-choked living room smile as they celebrate the online party they just held for 11 people in nine different states "and only had to wash one glass."

By 1985 CompuServe users could do much more. They could log on to the Electronic Mall (though at the time it wasn't clear what they could buy), scan flight availabilities ("on virtually any airline—worldwide"), look for medical advice on HealthNet, or seek sex counseling by sending an inquiry to the daily "Advice to the Lovelorn" column ("Hundreds turn to it for real answers"). Computers, too, were becoming more sophisticated: The Macintosh computer advertised in December 1987 had hard disks that stored "over 10,000 pages" and could incorporate an "Applefax modem" that "lets you send hard copy to any facsimile machine in the world."

In 1994 the World Wide Web was entering common usage. IBM was peddling its now virtually defunct operating system, OS/2, "the new 32-bit, multitasking, multimedia, Internet-accessed, crash-protected, Windows-friendly, easy-to-install totally cool way to run your computer," which allowed users to "warp" onto the Internet (a piece of corporate-created slang snitched from Star Trek that never caught on). Another innovation that apparently fizzled and died was WebTV ("The Internet. The ultimate resource. Now showing on a TV near you"), advertised in Discover in 1996. By then Discover itself was online: In 1995 it announced with fanfare that readers could now communicate directly with our staff "and read special Digital Content" by checking us out on the "Internet World Wide Web" at an obsolete site since superseded by www.Discover.com.

What else did the Web offer? In 1998 online shopping was fully available (the extinct egghead.com, a site now subsumed into Amazon, offered 30,000 products from its superstores as well as "action-packed online bidding" at its auctions); e-fiction had appeared, courtesy of IBM and Borders.com, and search engines like AltaVista dominated a pre-Google world. But perhaps the most dated of the technology ads was one that appeared in November 1999: It depicts a man sitting at a computer in a narrow Spanish street, oblivious as the rampaging bulls of Pamplona charge down upon him. "Y2K's coming. Don't just sit there," says the text, which promotes Iomega's Y2K Software Suite. "Back up your files, update, and protect your PC well into the next millennium." In our post 9/11 world, the ominous warning of the coming (and ultimately imaginary) computer apocalypse seems almost quaint.

It's not only gadgets that show the passage of time. To the health-obsessed eye of 2006—a time in which smokers are outcasts and the addiction akin to a moral vice—the profusion of cigarette ads in Discover during its first decade can be jarring. Nevertheless, in the mid-1980s, when nearly a third of the American public smoked (as compared with 20 percent now), the magazine's pages were splattered with them. The harmful effects of the habit were hardly unknown—the first major study definitively linking smoking to lung cancer had been published in 1950 in the Journal of the American Medical Association. Despite this—or perhaps to refute the risks—the smokers in the ads seem vigorous and healthy, rappelling rock faces, lassoing horses, batting snowballs with baseball bats, or as in a peculiar December 1982 ad for Newport Menthol Kings ("Alive with pleasure!"), sticking a Santa Claus beard on a woman's face.

Only after 1991—the year the family-friendly Walt Disney Company acquired Discover—do the cigarettes ads disappear, reflecting not only corporate policy but a sea change in the culture. In 1994 tobacco industry executives were hauled before Congress to defend themselves, en masse, for the first time—and were soon to face multibillion-dollar lawsuits by states seeking to recoup the cost of caring for people with smoking-related diseases. By 1997 the only reference to tobacco was an ad for Nicorette Gum Stop Smoking Aid. Health awareness, body image, and virility were creeping into public consciousness in the 1990s, with musclemen touting the benefits of bodybuilding machines like the NordicTrack.

In 1993 the baldness-battling remedy Rogaine pops up in the pages of Discover and in November 1999—what else?—Viagra. By 2005, however, diabetes drugs were being promoted—reflecting a near tripling of the incidence of diabetes in the United States in the past quarter century, from 5.8 million people with the disease in 1980 to 14.7 million in 2004. Obesity, too, was on the rise: In 1980 less than 50 percent of Americans were overweight or obese; in 2004, two-thirds of the population was fat.

Car sizes expanded along with the waistlines. In 1980 ads for the compact Ford Escort boasted a higher gas mileage rating than smaller cars like the Volkswagen Rabbit; 20 years later, gas-guzzling SUVs were racing through the pages of Discover instead. Nonetheless, a growing awareness of environmental issues began seeping into Discover's ad pages, reflecting new pressures on the oil and automobile industries and a new sensibility among consumers. In 1994 the Chrysler Corporation had a gaggle of hapless cartoon penguins peer through a hole in the ozone layer in its ad for new vehicles fitted with air conditioners free of destructive chlorofluorocarbons. Toyota promoted the "world's first mass-produced gas/electric vehicle," the Prius, in December 2000. By 2004, BP was styling itself "Beyond Petroleum," and GM was predicting a new generation of cars and trucks powered by hydrogen, "where the only emission is water vapor." Just one year earlier, the Shell Oil Company had printed the dread words global warming in an ad that invited readers to e-mail their opinions to its Texas headquarters. "We believe that action needs to be taken now, both by companies and their customers," their advertisement said. When an oil company trumpets the need to tackle climate change, you know that the world has been transformed.