Facebook is opening up, for better or worse.

Internet users can now search for Facebook members on the Facebook site without logging in.

"Starting today, we are making limited public search listings available to people who are not logged in to Facebook," said Facebook engineer Philip Fung in a blog post on Wednesday. "We're expanding search so that people can see which of their friends are on Facebook more easily. The public search listing contains less information than someone could find right after signing up anyway, so we're not exposing any new information, and you have complete control over your public search listing."

In a few weeks, these "public search listings" will be made accessible through Internet search engines like Ask, Google, MSN Live, and Yahoo. Fung said that "this will help more people connect and find value from Facebook without exposing any actual profile information or data."

Fung maintains that Facebook users who do not want public search listings can indicate as much on Facebook's Search Privacy page.

As Danny Sullivan at Search Engine Watch and other have noted, Facebook profiles that are linked to from outside Facebook have been accessible through search engines for months. Google currently lists 25,000 Facebook profiles. Sullivan said he believes that today's announcement reflects a change in the default setting of Facebook's privacy controls from "Restricted" to "Everyone" as Facebook optimizes its listings for external indexing and access.

For Facebook, the changes mean more traffic. For users, that translates into less privacy, unless they opt-out.