The offer seemed too good to be true. And for many who thought Microsoft was going to ship them free USB storage drives, it was.

Microsoft promised the USB drives earlier this year as part of a marketing campaign for its Windows Desktop Licensing program. Web surfers who correctly answered three very simple questions about the company's licensing terms were told that they would be sent out free drives loaded up with information.

Microsoft called the promotion, "Mystery Solved," to convey the idea that Windows' licensing terms need not be a mystery. The offer was widely publicized last February and Microsoft appears to have been overwhelmed by the response. On Friday the software company sent out an e-mail to participants entitled, "The mystery of the missing USB drive."

"Unfortunately, this Mystery Solved promotion was available in the U.S. only and while supplies last," Microsoft said. "Supply is depleted at this time."

Reaction on the Digg.com Web site, which publicized the offer last February, was swift and severe.

"Thanks for nothing, Bill," wrote one poster, referring to Microsoft Chairman and Chief Software Architect Bill Gates. "I've heard of vaporware, but not vapor-hardware."

"I'm a little bit upset, but I half expected to not get anything all along," said another. "Hooray for Microsoft! Pissing off customers by borking a promotion is a great way to prevent piracy!"

Microsoft executives were not immediately available to comment for this story.

The Mystery Solved Web site can be found here.

The IDG News Service is a Network World affiliate.