Back in 1990, before Twitter, Facebook, Amazon and Google, it was unthinkable that we would buy most of our shoes on the computer. Back then, the 10 best online shoe stores were the only online shoe stores you'd have to choose from. But if you fast forward to today, the idea of buying shoes online is as natural as toast for breakfast. Buying shoes online isn’t just about hitting up Zappos either. There are hundreds of places to get great…