I have been trying to make my own sense of the conversations last week about PLE and assessment. With a topic like that we could probably discuss until the end of time and never really get to a clear resolution... I am coming from the perspective of the world of business & research, and there too, the dynamic is the same.
So there isn't much I can really contribute on how to assess (or measure) a person's learning and whether it should be solely driven by the individual or guided in some way by the educator. Except, perhaps to say that, in the end, the learning is the responsibility of the learner and it is also good to have a kind of a map to explore a city at least for a start even if one decide to redraw it or discard it at the end.
What really interests me is to explore if, instead of talking about PLE in isolation, we should instead talk about PLEs and say, ILE for Integrated Learning Environment.
A PLE by itself is fine. It would help one person for its own learning and research. It would make for a more "user friendly" system. It would also help for making the learning more widespread, less reliant on one single source of knowledge. But it wouldn't necessarily leverage the value of connecting individual PLEs together.
If the learners can develop as a community to support each others, provide feedback (a form of assessment) and depend on each other's work to explore more, faster, etc..., then the network effect kicks in.
So, to me, the value is also in having some kind of hub to keep things together. Like the gRSS Hopper that Steve puts in place. This allows connection across the individual as well as, provides a way to monitor the development of the learning (community). Again here, it might be possible to set up some kind of external assessment of individual learning without that (but it would be probably cumbersome, time consuming and would any way, at least, require people to register) but that would be missing on the possibility to measure how the learning community evolves as a network.
I think that it should be possible to assess the learning that happens during a course like PLENK2010 by simply looking at the formation and evolution of the network. That's where the interesting bit is for me and it would require a mix of PLE and a system to link the participants together and monitor their interaction.