I was discussing over the weekend with a friend who is putting together plans for online learning at a college. My experience is that e-learning has very good intentions, but often misses the mark. Many colleges and universities start by providing discussion groups and forums on an 'if you build it, they will come' basis. A forum needs about 8+ regular posters to have any life, and a subject that provokes discussion (one that there is no right answer to the questions, or which has lots of details), but for every 10 forum members perhaps only 1 will be a regular…so that's 80 members before it comes to life.
An online learning site that is highly effective is IBM's DeveloperWorks. There are regular submissions of technical articles and tutorials from IBM staff about complex IT subjects. There isn't much need for deep discussion though, although there is opportunity to comment on pieces.
My interest is that I have built an e-learning authoring tool called Acce-Lerator for The Training Foundation and I would like to see it get used fully. There are a number of tools available for creating 'courseware', but Acce-Lerator is designed to be usable by just about anyone out-of-the-box. It's difficult to keep to this premise as the system grows as there are increasing requirements to put checkboxes, etc. for special behaviours, but the core system is still pretty simple. We then use the excellent Moodle Learning Management System to host the courses.
If I was designing an e-learning platform I think that I might include a wiki and task students to build the content. This 'pedagogical' approach means that individuals are active in building something rather than passively attempting to soak up information piped at them. The latter entails more and more complex technology to try to make the experience interesting, whereas the former can be very simple as it is the act of finding and adding the information that helps you to learn.