If there is one thing that Scratch is missing, it is an app. Just think of it this way, if there was a different version of Scratch for tablets, phones, and other devices, not only are there more possibilities, but Scratch could get more publicity. It is almost like installing Scratch on your own computer, but on mobile devices. You can always be making games.

There was an app on the Apple Store, but it was deleted by Apple's policy (pretty stupid, IMO). They are planning on making a HTML5 version over the summer/fall so you can use Scratch on tablets.