Most recently, we've used Stanford's EPGY math online. We are, however, using it through a homeschool group formed on this website, so we do not have access to the tutor feature that you get when you sign up as an individual. The cost savings is so substantial that we were happy to make that trade off, though.
What dd has liked about it are the audio lectures, although she does "mute" the voice at times when he is interfering with her thought processes. I do think that the flash player lectures that pop up are very useful and it has a good methodical method for introducing concepts.
We currently have chat, but I've been looking into a virtual world chat environment (like Sims) where students can take quizzes, complete assignments and interact with instructors and peers.
This sounds like something that we would find appealing. I like the concept of being able to form a virtual community for homeschooled gifted kids. Having access limited to enrolled students would also provide some degree of safety for the children.
