Can I repeat it another time: BANDWIDTH.
When you are looking to eLearning, the single most important thing is to have sufficient bandwidth. Fast enough and cheap enough. I was reminded of this again when I returned to school after the summer holiday only to hear that they had to disconnect our 100Mbs line, because the learners ran up such a huge bill that the school will be bankrupt before the year is out.
I realise that a lot of you are scratching your head at this, since you have fast and cheap internet. In South Africa however internet is slow and it is expensive. The department of education is looking into providing schools with free internet, but at the moment it is just for the use of staff. If you want the learners to connect, you have to pay for it yourself.
So my best advice would be for South African schools, get an uncapped line at a fixed rate. Because limiting the use when you pay per Mb is very difficult.
We tried to block anything unnecessary, but there are so many things that are ambiguous. For example Youtube can be used as an educational tool, but it is also the biggest gobbler of data. If you block it, there is a whole world of resources that you loose out on, but if you do not block it, I can promise you it will be used for everything else.