I remember using this interface when it was Google App Inventor a couple of years ago. It’s fairly intuitive, and with enough patience I can see…let’s say a tween getting it. These things still require an understanding of computer logic and how it works. I’m not saying that a younger child couldn’t do it, just that it will take some smart coaching.
I wouldn’t expect too see many projects coming from the grade school block, or any where else for that matter. These graphical scripting programs always seem to have certain limitations, which I think is to be expected when you remove the text aspect from scripting. Still though, I’m going to have to see what my 10 y.o. can do with it this summer.
Wired.com article on Google Blockly.