What made Microsoft purchase Minecraft?

This a very important thing that i need to know.

I am developing a game by myself, it's not complete but it has taken me 2 years already.

All i have to say it's a game that kids WILL love. I have put so much time into this game.

So one my question is what made Microsoft Studios purchase Minecraft from Swedish Developer Notch.

What makes big time companies like that purchase video games?

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