(FORTUNE Magazine) – Perhaps it's not the growth industry of the 1990s, but hundreds of startup manufacturers have added a new look to the $2-billion-a-year horseshoe business -- and roped in a new breed of farriers. The 30,000 plying the horse- shoeing trade in the U.S. include those who plan to leave corporate jobs for a second career. Among them: Keith Seeley, 35, a data-processing manager for SunTrust Banks in Tifton, Georgia. He is taking farrier courses and hopes to have a full-time business in another year or so. Even though the horse population is flat at best, there's plenty of demand for the service, says Seeley, who has owned horses since he was a kid. ''It's better than being inside a building with no windows,'' he says. Over the past decade, horseshoes have achieved a kind of market segmentation that puts Nike and Reebok to shame. There are now over 600 different types, each with its own shape, width, and weight, as well as 50 kinds of nails. Nineties-style marketing initiatives include the Hoof Express, published by Horseshoes Plus, a small supplier in Barrington, New Hampshire. The newsletter includes product updates and news about local farriers. Says Jacalyn Cilley, a University of New Hampshire marketing instructor who runs Horseshoes Plus with her husband: ''In most industries, a newsletter is hardly an innovative promotional technique. But here it's got everybody taking notice.''