It's absolutely astonishing to me that nobody ever mentions how Github handles viewing code. I always thought it's painfully obvious why Github won. They make viewing code easy. Duh. They have that nice little animation of code sliding in which lets me think that I'm not waiting forever, and I can actually navigate and explore other people's code.

I may overestime myself a little here, but I'm pretty sure that's the main/only reason Github succeeded. Not some new pricing scheme.