Not only does the code let you split the screen in two with an app on each side, but you can also go 1/4- or 3/4-size allowing for all kinds of screen arrangements. We've heard tell of this one coming, but it'll still be a cool feature, when it almost inevitably sees the light of day. [@stroughtonsmith]
Great, being used to 3 screens at works having just one at a time on the iPad bugged me (and some apps stop when they're sent to the background) I love the fact that Apple is following the lead of other devices, it would be stupid and arrogant not to follow just because they didn't come up with it first. The only thing that worries me is the big chance of having this functionality locked to the latest generation only.