Inclusionists believe that there should be no constraints on the breadth of the encyclopedia – that Wikipedia should include any entry that any contributor wants to submit. An article on a small-town elementary school is no less worthy for inclusion than an article on Stanford University.
Deletionists believe in weeding out entries that they view as trivial or otherwise inappropriate for a serious encyclopedia.
He posed it as a chioce. We can discover what an unbounded wikipedia can turn into, or we can discover how high quality a volunteer encyclopedia can become. But we can’t do both. He says maybe it’ll fork, but I doubt it, because then you have to duplicate effort for the overlap. Hopefully danvk will slap us with some knowledge.