While I was reading Snow Days Schmoe Days, I orginally agreed with the whole concept. However, there are a few things that I thought would cause problems with the "virtual classroom."
First of all, people need to interact, something that the virtual classroom does not provide. The load that using video streaming over broadband would put the current infrastructure, would cause problems for everyone.
Also, without supervision students can Facebook, download music to their iPods, and email. Ask them to configure their USB headset and troubleshoot mic problems and you get blank stares.
source:http://www.zdnet.com/blog/education/snow-days-schmoe-days-why-the-time-for-virtual-classrooms-is-now/4486?tag=mantle_skin;content