After all, although Microsoft rakes in billions, piracy of its flagship products remains a huge, costly problem, particularly in developing countries such as China and Russia. The Business Software Alliance estimates that 35 percent of software installed on PCs worldwide is pirated.
Nevertheless, 18 months after announcing the Windows Genuine Advantage piracy check, Microsoft faces controversy and backlash, including two lawsuits. Some say the company clumsily handled several elements of the program, including a key privacy issue.
"They have a right to say, `If you want patches from Microsoft, you know, you should let us make sure you're not running a pirated copy of Windows,"' said Gartner analyst John Pescatore. "That's a valid claim, and with the Windows Genuine Advantage tool, I think, they tried to go a little too far."
Microsoft introduced the piracy check in mid-2005 as a condition for downloading security fixes and other software, such as anti-spyware technology, from its Web site.
Now the anti-piracy check is also being sent to customers whose computers receive security updates automatically. For now, users can take extra steps to opt out of the piracy check. But Microsoft strongly encourages people to run it, calling it a "high priority update," and says the check might become mandatory at some point.
Once installed, the program checks whether it believes the user's version of Windows is legitimate. It gathers information such as the computer's manufacturer, hard drive serial number and Windows product identification.
Microsoft still offers important security fixes even if the company alleges the version of Windows is pirated, although those users can't get non-security downloads, such as a test version of the new Internet Explorer browser. Those users also receive a barrage of notices that they are running an illegal copy of Windows.
While Microsoft had told users the new software would gather information related to piracy, some people became alarmed when they discovered that the software also was performing a daily check-in with the company.
Microsoft said the daily "call home" was a safety measure designed to let the company shut the program down quickly if something went wrong. But critics saw the undisclosed communications as a breach of privacy and trust.
Marc Rotenberg, executive director of the Electronic Privacy Information Center, said the concern is that users did not know about or control the interaction.
"It feels very much like a digital trespass — you know, someone is getting access to your system without your consent," he said.