Minecraft updates today - it should be any moment now - with the feature I've been waiting for since it first appeared: Adventure Mode. They're also adding a demo mode, that lets non-registered users play for five days per world in singleplayer, thre's trading, a better inventory for Creative mode, tweaked how experience is distributed, added the ability to write 50 page books, more buildings for jungles and deserts, and included new blocks based around Emerald, pan-dimensional Ender Chests, a tripwire, and just so many more tweaks and fixes.
When I spoke to Notch last year, back when the game had only made around £30m, rather than what must now be around £100m, we discussed the Adventure Mode, and a number of elements he mentioned are already in there. Experience, achievements, villages. In fact, at the time, Persson described the idea of villagers as "this really silly idea" he wanted to do, places that offered parodies of MMO quests. Now, with this addition, it's something people will be able to add for themselves.
So what is Adventure Mode? It's a way of transforming the game in a really significant way - of making it into a place where stories can be told, and thus adventures had. Players won't be able to destroy or place blocks, which obviously seems quite at odds with the very point of Minecraft, but is of course so you can experience others' creations. People will be able to craft adventures for other players to have, especially with the aid of the new block that allows designers to program scripted events. This block might give out XP on completion of a task for instance, and of course will have billions of other applications as soon as players get hold of it.
With the addition of trading, too, there's a meaningful way for players of Adventures to get items without block destruction. Trading for goods, and fighting mobs, will equip you with the stuff you need. The newly added emeralds appear to be the main currency in the game, with villagers offering selling, buying or enchanting, depending on their profession. This will also, apparently, be the only way to get "bottles o' enchanting" and chainmail armour.
There's loads more being added here too, and it's well worth looking through the detailed list on Reddit.