From an enterprise perspective, a wiki can be used as a tool to collect experiences, insights, facts, opinions, lessons learned or other kinds of information from any corner of the enterprise. It can be seen as a tool for creating a culture of knowledge sharing, where fellow coworkers empower each other and thereby empower the entire enterprise.
A key to an enterprise wiki's succcess is of course that it is easy for anyone to contribute to it. If it requires a great deal of effort to share something with others, then most of us don’t bother to do it. But even more important is that as many as possible feel that they get something in return for their contributions, be it gratitude, credibility, respect or something else.
I also believe that enterprise wikis shouldn’t allow anonymous contributions. If anonymity is allowed and maybe even becomes common practice, the possibility to get in contact with the contributor for the purpose of person-to-person knowledge exchange is lost. This aspect of knowledge exchange via an enterprise wiki is very important. A person might simply not be aware of knowledge he/she possesses that might be very valuable to other people within the enterprise. Hence, it is not made explicit on the wiki. Or, the knowledge is tacit and requires face-to-face contact to be communicated. In this sense, an enterprise wiki can give people access to both explicit and implicit knowledge that exists within the organization. This, to me, is the great promise of enterprise wikis.