Ok well its been brought to my attention that Minecraft is soon going to become a hoebag to buy.
Pretty much What that says is Buy the game before the 20th or we will rip you off yayay!!!!
haha but seriously what is said in that is that all Alpha players, will get any and all future content for free like we were promised BUT! if you buy the game AFTER the 20th you'll have to pay for future expansions which I'm guessing are just the really big updates, you will still get all bug fixes and smaller content updates free, also note Notch says "Buying the game during beta will include all updates up until release, of course, and bug patches will be free."
So pretty much buy minecraft either while its still in Alpha or if possible.
Here's some links to pages I got info from:
http://notch.tumblr.com/post/2175441966/minecraft-beta-december-20-2010 (Notch's Blog)
https://www.facebook.com/minecraft?v=wall (this is the official facebook)