The results are different because Facebook uses certain filters and doesn't display sponsored results, said Matt Hicks, a Facebook spokesman.

In addition to requiring users to do an advanced search to find image or map results, the results format looks different from other leading search providers, another potential drawback, Sterling said. Each item appears in a box that lists the Web site, a description of it and a link. "The presentation of results is a little strange, it's a little unfamiliar for search results," he said.

However, the companies may view this as the first try, with plans to add more capabilities.

"As we evaluate user feedback and results we'll explore additional ways to integrate Live Search more deeply into the Facebook experience," wrote Angus Norton, senior director of Live Search product management at Microsoft, in a . He called today's service a first step.

In the future, Facebook should look for ways that search results and other content on the site can be more relevant to people in the context of their visit to Facebook, said Jeremiah Owyang, an analyst with Forrester Research. "This is a long-term play," he said.