Maybe you thought every pivotal Windows moment was a product release. Not so. As good as it was, Windows XP also unleashed Windows Genuine Advantage—or what we now refer to as “activation”—upon an unsuspecting world. It was the first step in evolving Windows from a “hobby” to what some would refer to as “Micro$oft.”

This attitude was nothing new. In 1976, Bill Gates penned “An Open Letter to Hobbyists,” where he complained that the amount of royalties paid by customers using its BASIC software amounted to about $2 per hour. “Most directly, the thing you do is theft,” Gates wrote, essentially equating sharing code with outright stealing.

Microsoft sought to curtail this activity with the release of Windows Genuine Advantage, which stealthily installed itself onto millions of PCs by way of a high-priority “update.” (Sound familiar?) Windows Genuine Advantage consisted of two parts, one to actually validate the OS and another to inform users whether they had an illegal installation: In 2006, Microsoft said it had found about 60 million illegal installations that failed validation.

Now? Virtually every standalone product Microsoft sells comes with its own software protections and licenses. If you want a “hobby” OS, you run Linux—which Microsoft also spent millions trying to discredit, to no avail.