I have been reading lots of papers recently about web2.0 adoption in large enterprises. It seems that the common occurrence is a small grassroots seed that grows with popularity into a larger more widely used solution.
I am referring to the IT consumerization which Gartner says will be "the most significant trend affecting IT in the next 10 years". While looking at my own organisation for my dissertation, I have come across multiple small-scale wiki implementations scattered among different departments.
On their own, each wiki was very powerful and an excellent improvement on the conventional tools for team collaboration in the 90's (email + MS Office), but in terms of consistency, cross-reference and compatibility they are actually creating the same siloed effect we started with. In speaking to one of the "Wiki-Champions", I also discovered that usage was not very high amongst the team members because the wiki was seen as a "gimic" i.e. There was no exclusive content on it which required them to use it, and also no management support of its usage.
I believe that IT managers have to recognise the user "urge" to use the social software tools as part of their working environment. The best way is to get in early, to put the tools in place so that at least when a team or project wants to create content in a workspace, they are all common, held on a single knowledge base (I don't like the word repository), and can be searched with all of the others.
One of the things that I have been concentrating on from the beginning is management support. If I engage the senior management approval for wiki usage by clearly displaying and explaining the KM benefits which could be realised, then I will get that exclusive content which will help ensure improved usage and sustained engagement with the system.