Since then, Ms. Fisherman-Ruff, 42, a publicist in Manhattan, has stockpiled a variety of products, including a discontinued eye shadow (also Chanel) and a custom-blended Prescriptives foundation, seven bottles of which currently reside in her refrigerator alongside the butter and cheese. Many women spend a lifetime in search of the perfect shade of lipstick, the ideal moisturizer or the prettiest perfume, only to watch their hard-won favorite go the way of the dodo. Until recently, these consumers had little recourse other than to register complaints with manufacturers" service centers, but now, thanks to social media sites, as well as company-run Internet chat lines, beauty companies are keeping closer tabs on which products their customers want brought back and responding to that demand with reissues, albeit in limited quantities and through select channels. "It's literally reshaping how the market is driven," said Karen Grant, a senior global industry analyst with the NPD Group, a market research company in Port Washington, N.Y., speaking of social media. Perhaps adding to the fervor is the fact that winning products won't be available in stores. Wine, the shade of Bobbi Brown lipstick that had the most votes in the United States, will be available only online via a Facebook link to start in October, while the winning shades of MAC products - a lipstick, lip gloss and eye shadow - will be available in August, also only on the company's Web site. But selling these products online or on television - on Saturday for instance, Carol's Daughter will reintroduce its Ocean collection, a three-product bath and body line, on the HSN network - changes the equation. In 2009, Drugstore.com made a deal with Procter & Gamble to carry select Max Factor items after the company stopped sales in the United States. Another company trying to pre-empt frustrated customers is the Britain-based Lush, known for making beauty products by hand with fresh ingredients. It has a so-called Retro line, which most recently included a Pineapple Grunt soap and All That Jasmine Bath Bomb. Once, the company brought back its Tramp shower gel because a customer wrote a note about how much her cat loved the smell. "It's not a hugely commercial thing for us," Hilary Jones, the company's ethics director in Britain, said of the program. It's about keeping the customer's good will. And, of course, her loyalty. After buying Erno Laszlo, the cult skin-care brand, last year with a group of investors, Charles Denton decided to pare the company's 127 offerings down to fewer than 60. Rumors spread over the Internet about which products would make the cut and which wouldn't, and eventually Mr. Denton, the company's chief executive, began personally responding to e-mails - as many as 200 a day - from worried customers. Partly because of those communiqués, he decided to keep two powders that had been marked for discontinuation. "The consequence of a poor decision could take 18 months to two years to filter back to the head office," Mr. Denton said. With social media you can take an instant read. That's fantastically valuable. And beauty behemoths are heading the call, as well. Last year the French cosmetics giant Lancôme brought back Blush Subtil in Cosmopolitan Pink, available for purchase on its site, in response to consumer demand. Next up? Possibly Aroma Tonic, a citrus-scented body spray with its own "bring back" Facebook page, which has over 370 "likes." "One person writes, then another person writes," said Gracemarie Papaleo, an assistant vice president for Lancôme. They rally together. Perhaps Carolyn Park, 28, who works in business development at a law firm in Manhattan, should mobilize the troops. Upon discovering that Guardian Angel Heat Protect "n Curl, a hair spray from Got 2 Be, was discontinued, Ms. Park, who stockpiles mascara and hand cream, among other products, snapped up four bottles for $7 each at Amazon.com. But "I'm on my last one," she said. And I haven't found a replacement.