Z:gnu-www-ja-rms-nyu-2001-transcript--99cdda-So, I looked for a way to stop/en

So, I looked for a way to stop that from happening. The method I came up with is called &ldquo;copyleft&rdquo;. It's called copyleft because it's sort of like taking copyright and flipping it over. [Laughter] Legally, copyleft works based on copyright. We use the existing copyright law, but we use it to achieve a very different goal. Here's what we do. We say, &ldquo;This program is copyrighted.&rdquo; And, of course, by default, that means it's prohibited to copy it, or distribute it, or modify it. But then we say, &ldquo;You're authorized to distribute copies of this. You're authorized to modify it. You're authorized to distribute modified versions and extended versions. Change it any way you like.&rdquo;