Many people are worried about how their personal information may get spread around when they submit it to a web site. And so they rely on privacy guarantees like this, from the privacy policy at Northwest Airlines' web site, nwa.com, which as I write offers the following assurance:

3) With whom do you share my information?

When you reserve or purchase travel services through Northwest Airlines nwa.com Reservations, we provide only the relevant information required by the car rental agency, hotel, or other involved third party to ensure the successful fulfillment of your travel arrangements. We also use information you provide during User registration or as part of the reservation process to customize the content of our site to meet your specific needs and to make product improvements to Northwest Airlines nwa.com.

We do not sell individual customer names or other private profile information to third parties and have no intention of doing so in the future. We do share User names and email addresses with our WorldPerks partners only for specific and pertinent promotional use but only if our customers have opted to receive promotional emails from Northwest and our WorldPerks partners.

Sounds pretty tight, huh?

Well, before you're completely reassured, you might want to look at this court ruling concerning a massive data dump which Northwest gave to NASA, of all government agencies, giving among other things the names, travel dates, credit card numbers, and traveling companions of everyone who flew on Northwest. In Minnesota, at least, the case was dismissed, though there may still be similar litigation ongoing elsewhere. Much of the commentary on the decision has focused on the part of the judge's ruling that says you can't rely on a privacy policy unless you can prove that you read it. But even if they had, quoth the judge, it wouldn't have mattered:

The language used vests discretion in Northwest to determine when the information is "relevant" and which "third parties" might need that information.

In other words, Northwest's assurance that they "provide only the relevant information required by the car rental agency, hotel, or other involved third party" is not only unenforcable, but despite appearances, it means absolutely nothing. According to the arguments of Northwest's own lawyers.

It's good to know how seriously they take their commitments.

(via, of all online publications, LWN).