Quicksilver is wise.
I AM a librarian, and our library has a workplace wiki for policies and procedures. It is … less than optimal.
Some things to consider.
Do you want a wiki, where EVERYONE can edit (ie, vandalize/damage) posted process or policy information?
Or do you want an online repository of information that general rank and file workers can ACCESS but not ALTER?
If you want the latter, you do NOT want a wiki. Calling it a wiki, and using a wiki structure and template will frustrate the hell out of everyone involved. (speaking from experience here)
If a database is what you want, build a nice flat database with a passcode entry tied to each employee specifically. Categorize the info banks by job duty, and hire/appoint ONE PARTICULAR person, preferably a general overseer familiar with all departments, to make sure it is kept up-to-date on current practice. Whenever employee reviews come up, make each employee demonstrate that they can access the database and find specific process or policy information to pass their review.
If you actually DO want a wiki, all of the problems that Quicksilver pointed out are true, and unless you have a way to FORCE your staffers into transferring their various knowledges into the wiki, they’re not going to want to do it.
The best of a bad lot is to assign each department or job function group to submit their specific workplace duties to the wiki by a particular date, or start facing sanctions as a group/department. What will likely happen is that the department will have at least one person who doesn’t actively hate the idea of a wiki (or is the most tech-savvy, or the scapegoat of the group), and that person will become that department’s “contributor” to escape group punishment. Like before, assign a SINGLE person to be the wiki admin, but that person now has to build ties with the wiki contributor from each work group, and make sure that they keep their information complete, clear, and updated.
Seriously tho - just build an online database instead. So much better.