While the media and lawmakers question future prospects for privacy if Google's planned acquisition of DoubleClick is allowed to proceed, the majority of U.S. adults appear to be unconcerned about the proliferation of personal information online.

That may be because people like being able to find out about one another. Some 53% of adult Internet users have searched for information about friends, family, romantic interests, or business colleagues, according to a report released on Monday by the non-profit Pew Internet & American Life Project. And 47% of adult Internet users have used search engines to look up information about themselves.

This perhaps explains why the Pew survey also found that 60% of Internet users say they are not worried about how much information about them is available online.

That's not to say privacy concerns don't exist. The Pew survey also found that 38% of online adults have taken steps to limit the amount of online information about themselves.

But not all those who actively pursue privacy do so out of fear. The survey further divides those who have tried to control the online information about themselves into those who don't worry that their personal information is online but nonetheless take steps to limit that data (17%) and those who limit online information about themselves out of anxiety (21%).

The Pew study suggests that people are becoming used to the availability and persistence of online information about them. "Unlike footprints left in the sand at the beach, our online data trails often stick around long after the tide has gone out," the report says. "And as more Internet users have become comfortable with the idea of authoring and posting content online, they have also become more aware of the information that remains connected to their name online."

How then to reconcile the recent privacy uproar over Facebook's Beacon or the specter of being "googled," which Microsoft SVP and General Counsel Brad Smith raised in testimony before the Senate Subcommittee on Antitrust, Competition Policy and Consumer Rights as a way to suggest that the combination of Google and DoubleClick means an end to privacy?

Is privacy really a legitimate issue if only a fifth of those online express serious concerns about it?

Some clearly believe it is and believe there's a market for privacy. TransMedia, an online media sharing service, today launched a media preview of a free collaborative rich-media Web mail application called Glide Free that's scheduled to debut on Thursday. The company is touting the virtues of e-mail privacy, noting that Gmail's practice of scanning users' messages to generate contextual ads is a misuse that would not be tolerated if the U.S. Postal Service did the same thing to generate ads for printed mail.

"A lot of money has been spent in public relations efforts by online services like Google, Facebook and MySpace to present their services as being ostensibly free," said Donald Leka, CEO of TransMedia, in an e-mail message. "We believe that these public relations efforts have been effective in impacting public opinion. People are largely uninformed regarding how their personal information is being used to make money by these online services. As more information becomes available to the general public, I believe you will see a significant shift in public opinion." In the meantime, most people appear to be content with "googling" and being "googled," despite the apprehensions expressed by Microsoft and others.