AoPS offered homeschool friendly classes and couldn't fill them.
AoPS could be easily used in school as long as there is a computer connection available. There are tons of questions in the books, alcumus, and at least some courses are doing weekly homework rather than the challenge sets that are due every few weeks. Alcumus and homework are online and the book problems are accessible without a computer. While courses do not follow an academic calendar, it would be easy to string a few courses together or to work on problem solving during off times or fun math topics.
I'd think a kid would need to be able to focus well and work hard independently, but a very mathy kid at 7 may be able to do that well. AoPS has multiple levels and doesn't just start at algebra anymore so it wouldn't be hard to get the right level, even for a younger child. And finally, the whole point of AoPS is to spend a *lot* of time thinking very hard about too difficult problems. Even without access to help, the time spent thinking hard can be beneficial and help can be given at home if needed.
