My DS was also very into Minecraft since he was about 3. Since he was delayed due to his dyspraxia, it seemed so odd to see a toddler who could barely speak zipping around on the site like it was nothing, building logical buildings, etc. I often wonder if his high PR score comes from Minecraft, or if he plays Minecraft because of his PR ability.
At six, he is still obsessed with it (and builds amazing things--the latest is some sort of operating mill), so I decided that he needs to "earn" screen time. He begs me to give him homework so that he can earn some more screen time.
I think Minecraft actually taught DS how to read. He was so obsessed with it that he was bound and determined to figure out what the names of all the materials were. He also started constructing signs by the time he turned 4, that said things like "GoThisWay". So there is a lot of educational value in it.
