Do you like online learning? Do you want to be able to tell others about the sites you use? Do you want to browse information about sites before you go to them? Then KAOS is the wiki for you!
Khan Academy is a philanthropically supported learning site. They feature most subjects, but they started as a math learning site. If you are struggling in a math class, or just want to strengthen your math skills, watch their videos and use their exercises. They have more than just math, too. Learn more about them on KAOS.
Scratch came out of a program that gives grad students at MIT hands on experience with all sorts of good stuff. It's a site made for kids to learn how to program with plain English drag and drop blocks. It also makes it easier to program animations and sound where it allows you to import sound and graphics. This is something you can't do on the coding section of Khan Academy.
Furthermore the KAOS wiki looks at other online learning sites like Duolingo for languages and various other sites. Stop by!