Check where your user community spends its time online, and use those destinations to promote the wiki. You could use social network tools like Twitter or Facebook, or write blog posts about the wiki and its value. Cross-pollination with social network tools can work both ways.
Many wikis provide widgets or macros that you can use to embed content from other web services onto your wiki page, such as a macro that will display live streams from Twitter, a set of photographs from Flickr, a YouTube video, and so on. You can use this sort of integration to attract people to the wiki who are already involved in other types of social media.
You can also use traditional, static websites as a way to promote your wiki through techniques like click-through buttons or banner ads. Email campaigns, mentions in company newsletters, and case studies at conferences and in industry media are also effective ways to raise awareness.
The best advocates for a wiki are invariably the community members themselves. If you make the wiki a place of real value where the community members feel that their contributions are recognized, then they will want to share and invite others.
As mentioned earlier, verbal feedback, such as a simple verbal “nice wiki article,” can be a very effective way of encouraging wiki use. However such feedback tends to be limited to the individual, or a physically co-located peer group and is not necessarily visible to the community as a whole
Here are some other techniques you can use to recognize and reward contributions for a community which includes remote contributors:
In a points system, people are given points based on types of activity. For instance one networking site I use has the following scheme:
The concept behind this approach is to give the biggest contributors to the community the most visibility. A good points system shouldn’t be designed just to help earn a better position, but to encourage people to do the things that are going to help everyone get the most value from the community
Once you have a way of tracking who the most active members of the community are and who contributes the most, you can recognize those contributions by developing categories of users. Many online forums already use this technique, where they apply different “ranks” as the number of posts you add increases.
Applying some sort of reward to the top “rank” users and contributors can make activity on the wiki a desirable activity with a tangible benefit. That benefit could be peer recognition or even a financial reward.
One software company I have worked with recognizes their top customer contributors each year as MVPs and in addition to the usual T-shirts and coffee mugs, gives them a free personal annual license to the software, discounts to their user conference, and early access to product releases.
Another technique to recognize contributors is to have a series of spotlight articles on the wiki homepage. These can either be articles by your MVP contributors or interesting articles by new contributors. Rotating these on a regular basis, such as once a week, keeps the front page of the wiki fresh and provides more opportunities for recognition.