On the Web's Cutting Edge, Anonymity in Name Only

Websites are gaining the ability to decide whether or not you'd be a good customer, before you tell them a single thing about yourself.

The technology reaches beyond the personalization familiar on sites like Amazon.com, which uses its own in-house data on its customers to show them new items they might like. By contrast, firms like [x+1] tap into vast databases of people's online behavior—mainly gathered surreptitiously by tracking technologies that have become ubiquitous on websites across the Internet. They don't have people's names, but cross-reference that data with records of home ownership, family income, marital status and favorite restaurants, among other things. Then, using statistical analysis, they start to make assumptions about the proclivities of individual Web surfers.