"Unschooling," a particularly unstructured form of homeschooling, captures the attention of the media on a semi-regular basis. See for instance this CNN article from last summer: "Unschoolers learn what they want, when they want." Psychology Today blogger Peter Gray launched an inquiry into unschooling with this post. And, a recent Slate article by Dana Goldstein on the anti-progressivity of homeschooling also mentions unschooling specifically.
Advocates of unschooling and critics alike seem to understand the practice as a radically "child-centered" form of education. Unschooled children pursue the topics in which they are interested, at their own pace, with help only to the extent they request or welcome it, all while following sleep and work cycles that suit them.
However, this emphasis on unschooling as "child-centered" distorts the vision of unschooling's intellectual father, John Caldwell Holt. Holt recommended getting children OUT of the spaces constructed just for them and into the already educational environments offered by the adult world and its cities, libraries, workplaces, etc.
Just about everyone claims that their form of education is "child-centered," anyways -- they just disagree as to what that entails. And of course, children require certain kinds of care and protection commensurate with their developmental levels. This is true whether they're spending their days in a school or not. But a child-centered place, whether in a school or in a home, and even when created with the best of intentions, will be morally artificial, socially strained, and educationally de-motivating.
Unschooling as per Holt is not about keeping your child home in a comfortable, personalized edu-bubble. Rather, unschoolers are afforded the valuable freedom to go and do real things with other people, learning how to negotiate various social situations in the process. And the real world does not revolve around the child.