In collaborative learning, teachers, assistants, students and the web resource interact in an electronic collaboration system
Seems particularly valuable in K-12 arena
Also natural model for collaborative research
Note systems like Lotus Notes are "just web-linked object brokers" from this point of view (and again should be avoided as not built around modern object models)
All approaches use basic asynchronous tools such as electronic mail, bulletin boards and searchable repositories
Can record synchronous sessions for later asynchronous replay
One need not chose any one approach as can support all of them with a (preferably database back ended) web site linked to a suite of collaboration tools
Note just as we can link asynchronous--synchronous--collaborative, we can also link education and training
Note modular educational objects naturally support smaller units of achievement certificates