When weight-loss marketer Atkins sought new buyers for its branded diet food, it looked no further than the Internet. But what started as a simple couponing campaign quickly turned into a viral wild storm.

Atkins in September launched a lead generation and trial campaign to drive sales of its shakes. Its goal was to distribute 20,000 coupons and bolster its database for future marketing.

People who opted in for special offers from the company received an e-mail directing them to a microsite to download a coupon. Atkins also marketed the promotion via custom questions in which people selected from various offers, including the Atkins promotion.

The offer was so popular that recipients began spreading the word about it. Some posted the offer and URL in their blogs and on message boards. Others called the company directly for more information.

“Atkins got 200 phone calls during the first day we started the promotion,” Brad Powers, CEO, Active Response Group, the agency that handled the campaign, said. “It was a compelling offer.”

To help with demand, Active Response Group set up a second microsite for Akins to direct callers to the coupon offer.

As a result, Atkins handed out 26,000 coupons alone to people who were referred by friends, blogs and the company’s customer service department. In all, the company distributed 28,376 coupons.

“Having a good offer can have a tremendous lift on the overall campaign goal,” Powers said.

In addition, Atkins built up its database by more than 15,000 names.

“It shows that how wonderful viral marketing can be when it’s associated with a particular offer or promotion,” Powers said.

Banners ads also supported the campaign, which ran for four weeks.

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