I have a great idea! There's lots of Chinese on the Intarweb, and the computer already knows which character it is, so it can provide a lookup service! It'll be a great learning aid! I can implement it as a web proxy which rewrites pages to include links from characters to definitions!
In reality, it's been a way to avoid boring drills, taking classes, or any of the other proven ways to learn a language, and it hasn't helped all that much.
Moral: if you want to learn a language, don't write software.