Three years ago 1-800-Flowers, long a pioneer in Internet marketing, became the first national florist to create a fan page on Facebook. It used the free page to build relationships with customers and sell selected products, but it spent very little money advertising on the site. In January, however, the company began buying a different kind of Facebook advertisement. "Sponsored stories," as they're called, let marketers pay to turn actions people take on Facebook into promotional content. When members click a thumbs-up button to signal that they "like" a product or brand, for example, a simple ad appears on their friends' pages: "Julia Smith likes 1-800-Flowers.com." Those friends can click a Like button on that ad, which then shows up on their friends' pages, and so on.

Thanks in part to those ads, the company now has more than 125,000 Facebook fans, more than twice as many as it had at the start of the year. Now, says 1-800-Flowers president Chris McCann, "We look at Facebook as core to our marketing program."