Google, the incomparable search engine, is heading in what seems to be a natural direction: The company is testing a free e-mail service, tentatively called “Gmail,” but a strange feature distinguishing the service from competitors is raising eyebrows among privacy experts.

“Google E-mail: Room for Regret?” by Jeff Gelles, in Saturday’s Philadelphia Inquirer, spells out the creepy details:

Google’s Gmail, still in testing, offers a gigabyte [of storage] -- more than a billion bytes. That’s 500 times as much as Hotmail, and, in e-mail terms, an amazing chunk. […]

So what does Google get in return?

Nothing less than your permission to read your incoming e-mails, and target ads to you based on their content.

That’s right. You could be reading a friend’s paean to Norah Jones’s latest CD, and up pops an ad for the iPod. Or an e-mail from an airline, and suddenly see an ad for a car-rental company. […]

Beth Givens, executive director of Privacy Rights Clearinghouse[,][...] says that many descriptions about Gmail miss a key point: that Google’s scanning target is the e-mail you receive, not the e-mail you write.

“They’re now making some noises that there will be an opt-in” for Gmail subscribers, Givens says. “But they’re not talking about any sort of opt-in provision for those nonsubscribers who send you e-mail. That’s really the crux of the problem.”

If it’s any reassurance, Gmail’s privacy policy volunteers that your e-mails won’t actually be read by any prying human eyes. The scanning is “a completely automated process.”

There’s more:

Google says copies of your Gmail “may remain on our systems, even after you have deleted them from your mailbox or after the termination of your account.”

I’m normally not the paranoid type, but I think I’ll pass.