I started participating in Wikipedia -- I added a few tidbits to the image registration article. The wiki phenomenon is pretty cool; I think its pretty philosophically consistent with the distributed collaboration concept that underlies theWheel. theWheel needs to be web-enabled allowing multiple people to add nodes / adjust weights / etc. Then one of the main problems of Wikipedia, that there needs to be agreement on content and order, is no longer strictly necessary, because it is possible to interpolate different link weights from a number of different sources.
I think the perfect application of wiki-like collaboration would be in the generation of ontologies for the Semantic Web. The quality of an ontology seems to be related to how well it represents the consensus mental model for the group of people who will be using it to structure their collective knowledge. So it seems only natural to use a collaborative tool like a Wiki to evolve an ontology.
Of course, there are technical issues to be addressed. For instance, certain logical consistencies need to be maintained. But, using description-logic based approaches like OWL, consistency checks are relatively straight-forward. And its not like Wikipedia is absolutely consistent anyway -- at this point, inconsistencies among knowledge within Wikipedia's articles have to be vetted slowely by humans.