Your corporate environment will dictate the success or otherwise of your wiki implementation.
In many cases, just releasing access to a platform will bring benefits immediately,with staff eager to collaborate and share information. In other cases it will "die on the vine" without a concerted effort to drive usage, and work on the culture within he enterprise.
In any case, some pre-planning, and review of what you expect to achieve would be recommended for any enterprise, once a wiki is up and running, and being used, it can be difficult to make necessary changes along the way.
The technology is readily available from externally hosted SaaS models to in house hosted, or if you have time and money, develop your own! I have used both in house hosted, and external SaaS models, for me they were very similar, the benefit of the external model would be to simplify access for remote employees, rather then have them come back into the corporate firewall. This approach however may have some limitations depending on the data you are storing on the wiki (risk management may need to be involved).
The best approach is to give it a go! With a smallish team, willing to try something new, failure was not a major concern for us. We were willing to give things a go, and see what worked and what did not. Some of our thinking paid off, and some was not quite right, but in the end we are still running the wiki and it is still being used. the best part is, we have all learnt, and, corporate information now has a shared home we can all access.
