The tablet question just doesn't seem as relevant to mathematicians as the other questions are, and SuperUser really seems like the right place for it. It's well-known that the "let's have one giant Q&A site and just tag everything" solution doesn't work, so I think every question should be obviously more interesting to mathematicians than to other people. There's nothing wrong with visiting other sites for your other interests. I confess that I can't exactly describe when a question strays from a mathematical interest to some other interest, so we'll just have to feel it out.
]]>(One could always add an appropriate tag so those not interested can ignore such stuff)
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