In the next patch,the new Achievement system that will be added to the game.
In his blog, Notch states: "Achievements will NOT be chores like “cut down 10000 trees”, but rather challenges like “ride a pig off a cliff”. Stats, however, will be used to keep track of how many trees you have cut down. The long term plan is to show achievements and stats from the profile page on minecraft.net as well, in case you want to brag."
Also pet wolves will be added