It’s the Year of the Dog in the Chinese calendar, and Boulder, CO-based Only Natural Pet Store, which sells a number of products for dogs, decided this would be a fine time the time to overhaul its e-mail newsletter. In February it modified the content of its weekly newsletter from strictly product descriptive messages to informative articles and customer reviews. In the months since, revenue has jumped 660%, with sales generated directly from links within the e-mails up 147%.

The first of the new-style e-newsletters included an article about a dog’s busy social life. Another story, “Urinary Incontinence: Natural Treatment Options for Dogs & Cats,” offered reasons for the problem as well as solutions. The newsletters now include a number of images as well as conversational copy, says director of online marketing Julie Dye. “It really kicked off a higher interest level because it was funny and quirky.”

The number of subscribers almost instantly increased 16%, with nearly 1,000 new subscribers each week, Dye says. Catalog requests and response rates have also increased with the new e-mail newsletter. The newsletter currently goes out to about 56,000 people a week. Only Natural Pet Store doesn’t rent other lists or sell its own, Dye adds.

When it relaunched the e-newsletter, the merchant began using StormPost e-mail system — with tracking and testing abilities — from New York-based performance-based marketing provider Datran Media. The new e-mail program allows Only Natural to track standard metrics such as deliverability and order size, as well as other measures such as clicks per link and margin per subscriber.

“Before, it was aggregate knowledge — we knew how much revenue an e-mail made and basic stats,” Dye says, “but we couldn’t test multiple scenarios easily and find out what really works for us and our customers.”