If you want a lesson which is 7/24, you should use campus.dokeos. Because it has lots of advantages, because it is very useful and because lots of teachers use this site. If we get back to the advantages, for example if you want make a quiz which has multiple answers, you can do easily with dokeos. For example, It has chatting area among students, if they want to chat to online their friends, they can chat how they want; maybe it is about the lessons, maybe it is about the teacher. By the way there has lots of sites about online classroom but the most useful site is dokeos. So as you see it has lots of advantages, however ; it has just one disadvantege. The disadvantege is changing it means that the interface changes lots of time and it takes up time..