Markus Persson recently announced on Twitter that his game has built up 2.5 million sales. Not bad for a game that won't officially launch for another five months. According to our napkin math, pre-release versions of Minecraft have earned over $33 million for developer Mojang.
Minecraft's potential cash flow doesn't end at PC, as a limited version of the title is also planned for Xperia Play, under the moniker Minecraft Pocket Edition, while a console version of the title is also being worked on exclusively for Xbox 360, featuring Kinect and cross-platform functionality with the PC for this winter. While that "won't be a straight port," and will not be developed by Mojang, it still stands to pocket the developer some more money.