Tools that personalize the Web are not new. For years, people have been able to customize their home pages on sites such as Google.com and Yahoo.com. Similarly, e-commerce sites such as Amazon.com have long relied on recommendation tools to fuel additional sales.

So what's new? Previously, Web sites added automated recommendation tools to their e-commerce offerings to get you to spend more money. Now, it's about getting you to spend more time. The goal of the new generation of recommendation tools is to encourage visitors to stay as long as possible on particular sites and, in the process, deliver as many ads as possible to users - without alienating them.

Despite the challenges, many see recommendations and personalization as the next wave. If 2006 was all about community and user-generated content, 2007 and beyond will focus on individual desires.

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