Align wiki to mindset
As any wiki improves, it documents its own practices better and better, and becomes more consistent in its advocacy of its own mindset. For instance, a wiki that can avoid access control leans towards soft security and what may (not what can) be done by users. The need to support factions and credentials formally may be reduced to a minimum since it's easier to socialize taxonomy where that is a basic function shared by all users.
Any attempt to verb:align anything requires understanding of what the mindset of the organization is, e.g. fair trade, green telecom, or whatever. Only once you've done this should you be trying to have decisive goal discussions in the wiki itself, else it'll just be shut down by the usual suspects who do not respect the wiki's own mindset, which is not (yet) that of the organization that supports it. Slowly organizational protocol must address the gap between wiki users and not.
Choice of wiki software can determine outcomes: Mediawiki has social features that encourage users to talk to each other and cooperate, so mediawiki-based services are more likely to result in ongoing social relationships. While tikiwiki has more different interfaces and more fine grained content and access control which interferes with a social purpose since the number of people who can see and edit any given page is smaller and thus much more fragmented as a community.