"Train up a child in the way he should go: and when he is old, he will not depart from it." Proverbs 22:6
Used to be "eyes on the teacher" was good enough and if you could get away with passing notes and that sort of thing during class? You felt quite clever indeed. But the computer doesn't turn around to write on the board or help another student. The computer can now track everything about your kid with new technology and webcams. All the resulting data is kept somewhere.
Education Week mentions that there are privacy concerns, but fails to interview anyone about them except some school administrator who (God bless him!) would probably sell the kids and their data up the river for a nickel if it improved test scores.
The science on electronics and instruction is evolving, however. Recently, NPR came out with an article claiming that some so-called "educational" toys could be counter-productive for younger children. It would be interesting to see an independent study about the effects of computers and learning for older elementary students and/ or teens.