What is this?
It's a collection of tutorials designed to help new Ubuntu users, in particular those coming from a Windows-using background.
What is Ubuntu?
Ubuntu is an operating system based on the Linux kernel. There are many operating systems that use the Linux kernel (sometimes these are called "Linux distros"), and Ubuntu is only one of hundreds of these. I don't recommend Ubuntu to everyone, but here are some things that make Ubuntu unique among Linux distributions:
Read more here.