Even when schools strove to make sure their computers were only usable for educational purposes, as the case went in Texas, students simply found easy ways around the blockages, such as accessing Spanish-language websites when only the English-language ones were blocked (a bunch of white-collar, English-speaking 'educrats' surely came up with THAT brilliant plan!).
This is a short, 1/3-page article, but it's well worth reading. It seems particularly relevant in NYC these days, since Joel Klein's big plans for the DOE's future appear increasingly to be centered on online education (credit recovery, School of One, or whatever). This article at least provides background on the research-based downside. Also, I've heard people at schools (administrators, teachers, PTA's) talk many times before, with the very best of intentions, about providing computers to students in low-income families, automatically assuming that such a gift can only be beneficial, a sort of "equalizing of the playing field." I've done it myself and always just assumed it was for the best of reasons. Now I have to say that I'm not so sure, or perhaps it needs to be coupled with some appropriate caveats and parent/child education.
To a remarkable extent, everyone from Gates and Jobs to politicians and the media have convinced us that computers are an indispensable tool in children's education, so much so that it has become an article of faith, something that few people ever bother to question. Like any tool, we have to learn how to use it wisely; the studies from Mr. Stross's article suggest that such is often far from the case.