In the history of corporate marketing, a host of companies have implemented “Us vs. Them” campaigns to attract customers: Coke vs. Pepsi, Hertz vs. Avis, AT & T; vs. Sprint vs. MCI vs. everybody else.

In the Internet realm, a similar contest is brewing: EarthLink Network Inc. vs. America Online.

Earlier this month, Pasadena-based EarthLink debuted its “Opt Out of AOL” campaign, aimed at disgruntled AOL customers.

Every AOL customer who switches to EarthLink will receive one month of free service, a sequence of “change of address” e-mail notifications and a handbook entitled, “For AOL Graduates.” In addition, EarthLink will donate $50 to the Electronic Privacy Information Center, a Washington, D.C.-based think tank that calls for increased security measures in guarding personal information on the Internet.

So far, the campaign is little more than a series of messages on EarthLink’s Web site, but that could change next year. Company spokesman Arley Baker says that ad agency BBDO West has created a television, radio and direct mail campaign for launch at some point in 2000. He declined to reveal how much EarthLink is spending on the campaign.

Part of the marketing push will actually come with the cooperation of AOL. EarthLink is buying AOL’s subscriber list from its rival and will send mailers to everyone on it, urging them to make the switch, Baker said.

“I haven’t seen anything else out there like this (campaign),” said Kirsten Kappos, vice president of investor relations at EarthLink. “It’s a concept we’ve had since the early days we call AOL our farm team. Our notion is that if you want to take off your training wheels and really surf the Internet, you can do it through EarthLink.”

The campaign was developed after Kappos became aware that AOL about a month ago had notified all its subscribers that they must fill out a new online form specifically requesting that their personal information not be released to advertisers even though many had already stated their preference on that issue when they first signed up.

“If AOL customers have to take the time to change their marketing preferences, they might as well take the time to switch to us,” Kappos said.

In the hyper-competitive Internet service provider market, portraying itself as the scrappy “other guy” may serve EarthLink well.

“There is something with American consumers that particularly responds to that underdog aspect,” said Jennifer Beever, a consultant who specializes on marketing campaigns for tech companies. “Sure, a lot of people use Microsoft products, but they kind of roll their eyes while they’re using them. With EarthLink portraying themselves as sort of a second-comer to the marketplace, it gives them an opportunity to look at what the headliner is doing wrong, go after them on that and hit them hard.”

In recent years, EarthLink has run a campaign to attract AOL customers that included a “Get Out of AOL Free” card, offering a free service period for subscribers who make the change.

Kappos said she does not know how many customers have switched over to EarthLink directly as a result of the marketing efforts. She did say that 70 percent of EarthLink’s customers switch from other ISPs, and of that 70 percent, 30 percent come from AOL.

Officials at Dulles, Va.-based America Online did not return repeated phone calls seeking comment.

The mudslinging is almost entirely one-way: AOL never mentions competing ISPs in its own advertising, perhaps because as the dominant player, it doesn’t have to.

AOL has about 19 million subscribers worldwide. EarthLink currently has 1.5 million, but that will jump to 3 million after its merger with MindSpring Enterprises is completed during the first quarter of 2000.

“If you look at some of the charts published about the number of Internet users currently vs. the potential number of users, any ISP has an amazing opportunity,” Beever said.

But the EarthLink/MindSpring combination still will be a distant second to AOL, and some analysts say that EarthLink may have to move beyond taunting tactics to reach a wider group of customers.

Right now, it costs between $150 and $200 in marketing costs to sign up a single ISP subscriber, according to Zia Daniell Wigder, an analyst with Jupiter Communications. To make this kind of spending effective, she said, companies should show more examples of how they differ from each other and less attitude.

“AOL is the 800-pound gorilla that everyone is trying to take a swipe at,” she said. “What EarthLink is doing is not necessarily underhanded, it’s just one of the possible tactics. OneMain.com is another one that’s going up against AOL, but they’re using the marketing tactic of being the ISP for the under-served rural market, as opposed to the nationwide, blanket approach used by AOL.”