Experience orbs are a possible new item that will come out in beta 1.7. They are golden balls that may be droped from enemies. The Orb wasn't officially conformed by Notch, but he confirmed that a hidden clue of something that will be added to beta 1.7 is in the picture of the new lighting and the blurred 1.7 change-list.
Possibly proof For The Inclusion Of The Orb
the picture without the orb
the picture with the orb
the 1.7 "change-list"
The decoded change list
In the lighting system photo a small yellow spherical shape can be seen on the left side of the screen, but a day after the photo was published Notch claimed it had an "Error" and posted a new one, this time there was no yellow sphere. Later Notch shown a picture of a 1.7 change-list although it was completely blurred out and was, at first, though of as a joke, but then Notch stated that one of the pictures with the new lighting system and the change list had a secret in them[1] and people all around the web started speculating. One of this speculating was that the tabs at the top of the change list, that where partly deleted, could be decoded. After successfully decoding it the tabs red:ExperienceOrb.java, changelist.txt, Level.java, Tile.java,HugeMashroomTile.jav(a?),HugeMashroomFeature.(java?),RandomLevelSource(cut) There for the yellow sphere might be an experience orb. As of now Notch had neither confirmed nor denied this is the answer, but he did say that the answer was found[2]