Ok - so how do you know if you're "over-learning" - what are the signals for you?

Learning by problem solving.

I just try to solve problems one at a time. And usually break a hard problem into smaller easier ones.

When I can't solve a problem it's usually time to learn more until it's solved. And when it's solved I go to the next one.

I have created a programming language with this method without even knowing where to start.

I guess, the internet (accessibility of information) is the main reason that eliminates the need to learn stuff beforehand.

Maybe I should change the title to something like:

Learn as you go! :)

Aah that better explains what you mean!