Ubuntu is a community developed operating system that is perfect for laptops, desktops and servers. Ubuntu is and always will be free of charge. You do not pay any licensing fees. You can download, use and share Ubuntu with your friends, family, school or business for absolutely nothing.
The Debian Project is an association of individuals who have made common cause to create a free operating system. This operating system that we have created is called Debian GNU/Linux, or simply Debian for short. Debian is produced by more than a thousand active developers spread around the world who volunteer in their spare time.
The GNU Project was launched in 1984 to develop a complete Unix-like operating system which is free software - software which respects your freedom.
"Free software" is a matter of liberty, not price. To understand the concept, you should think of "free" as in "free speech", not as in "free beer".
The name "GNU" is a recursive acronym for "GNU's Not Unix!"; it is pronounced g-noo, as one syllable with no vowel sound between the g and the n.