Xmind - Xmind is a brainstorming and mind mapping application.
Don't Make Me Think - Originally written in 2000, Don't Make Me Think is one of the original books on web design and usability. Although it's been around for a while, the goals and lessons of the book are universal and apply to websites today.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Coursera - "Compilers" by Stanford - The course explores how high-level languages are compiled to low-level assembly.
Coggle - Coggle is a simple, beautiful, powerful way of structuring information.
The Elements of Typographic Style - The primary form of communication on the web is through text which makes typography one of the most important aspects to design for.