Until recently, predicting what shoppers want, and then getting them to purchase it has been a crap shoot. While you've probably gotten emails from Amazon suggesting books to you based on past purchases, the newest techniques use complicated algorithms that consider information such as when, where, what, and how much you purchase to send you highly-targeted emails designed to get you to buy. Enter today's success story: Proclivity Systems, a start-up that launched in 2006. They're one of the companies leading the way in the new field of predictive online marketing, according to an article in yesterday's Times. Eight months ago the company introduced its new "Proclivity Mail" system, which uses an algorithm to analyze a shopper's web activity, and then sends them targeted e-mails designed to get them to buy. Since then, the company—led by a 32-year-old former geneticist—has picked up major clients like Barney's New York and Alaska Airlines. Barney's says that their online revenues increased 10% after implenting Proclivity's software, and is considering using it in-store. For more information about Proclivity, check out their profile in this month's Fast Company.