The FCPS uses websense to block web pages. (
http://en.wikipedia.org/wiki/Websense ) All internet page requests go thru websense servers. If the page is on the blocked list, then you get the familiar "this page has been blocked in accordance with your organizations interwebnets use policy"
All internet content filtering servers were up during the period of unblockedness, so it was not due to servers being down. The county did move to the FCPSEDU domain but that has nothing to do with websense. Websense probably did some kind of upgrade which reset the "deny" category. THat includes sites like facebook that arent harmful or malicious but do not help the school's mission. Our friend Robert Afnani's (see
http://www.fairfaxunderground.com/forum/read/2/73225/73225.htm) site was also unblocked which leads me to that conclusion.
Youtube is still acessible from some schools but not others, which is interesting becuase when a page is blocked by one school and added to the deny list, it is automatically blocked by all schools. This anomaly existed prior to the period of unblockedness, however.
If you really want to know, you could email the IT dept at
ITservicedesk@fcps.edu
they will be pleased to help you out.