In all of the coverage I've read about Microsoft's rumored bid to acquire Mojang, I haven't yet seen any talk of Minecraft as a Platform. Minecraft: the Platform, is far more interesting than Minecraft: the Game. It's interesting to Microsoft, it should also be interesting to other big players in this space.
When I say Minecraft is a platform I mean it in the same way we say the Web is a platform. If you don't believe Minecraft is a platform then go ask any of the thousands of plugin developers and server administrators who are in freefall since the recent DMCA Takedown.
Minecraft has become Important - too important to be controlled by a boutique game development company in Sweden. The thousands of developers and administrators who build on top of Minecraft now see this. Microsoft see this. Learning the Minecraft protocol and how Minecraft servers work, will be important to software developers in the same way learning HTTP and how web servers work is today. There, I said it.
I'm ambivalent about Microsoft acquiring Mojang. Will they Embrace and Extend Minecraft as they've done with other categories? Let's hope not. On the other hand, some adult supervision and a Plugin API would be welcome. Mojang have the financial resources but lack the will and focus needed to publish and support a Plugin API. Perhaps Mojang themselves don't realise just how important their little game has become.
An interesting thread on reddit spells out the alternatives for developers who want to build on an open Minecraft platform. Me? In my down-time I'm going to stop reading the book I was reading and go read some source code instead. It may come in useful some day.