Point #5 raises the fish/fishing rod principle for me. The following is not a wiki story, but the principle holds:

In a previous job, I created little "how to" demo nuggets and posted them in the public folders of the email exchange system (because my MD wouldn't spring for a learning repository). The key was working with the Helpdesk, whose standard responses to requests for assistance tended to be either to tell the person what to do or to do it for the caller using LAN assist. Instead, I got them to point the callers at the nuggets, where these existed, and to keep me informed of FAQs for which further nuggets could be developed.

By contrast, at the beginning of my MA course, I created a wiki for the cohort. The intention was to build up a glossary of related terminology, as well as recommended reading list. When I mooted the suggestion, it was enthusiastically received. But because there was no signpost directing traffic in that direction, it wilted and died. People opted to email the lecturers with their questions instead and, out of a force of habit, the lecturers repsonded in the same medium.

By contrast again, because it was a requirement to participate in the online discussion forums in order to pass some of the modules, those saw very lively traffic.

There has to be a signpost. The resource has to make it onto people's radars, and that is only going to happen when there is buy-in in the right quarters (which doesn't necessarily mean from senior management!)