The previous example is only one way in which the collaborative aspect of Wiki can come into play. Many wikis are run primarily as open discussion forums. This function is natural for a fully open coauthoring tool, and in many ways better than traditional threaded-comment boards, mailing lists, or email.
Wiki communities vary, depending on a particular wiki's purpose, scope, openness, and availability. Some attempts to create a Wiki community apparently remain just another self-publishing tool; others, especially Ward's WikiWikiWeb, attract a diverse and active crowd willing to contribute, causing content to grow at amazing rates. Most fall somewhere in-between, "seed" content dominating, but with a small and hopefully expanding core of regular and contributing visitors. Community growth and maintenance remain imperfectly understood fields, awaiting further study in order to grasp their dynamics and underlying rules.
An overriding factor in any community is that visitors find enough of value to wish to return and become regulars. This core content can be anything, but must either be on a topic that visitors are motivated to contribute the initial content to, or consist of seed content that is interesting and extensive (or changing) enough that it alone can attract visitors. In either case, visitors must be encouraged to interact and contribute their own writing.
With few exceptions, it appears necessary to ensure sufficient "scaffolding", so that visitors understand what Wiki coauthoring means, and can find it easy to contribute. One workable way is to include "comment forms" on the page as it is displayed. For many visitors who are used to static Web pages and indirect comment links to email clients or guest book scripts, merely displaying an "Edit this page" or "Add a comment" link, however prominent, is not enough.
Figure 2 shows such a visible comment form, which is a much stronger (and labeled) invitation to contribute material than just the admonition in words. In addition, this now becomes a one-click operation for the visitor: type and post. It's readily apparent even before any action is taken what the intent is, compared to the less obvious method of a hyperlink to some other (unknown) place, such as "Search" in the top row.
Figure 2 Wiki page with explicit comment form inviting visitor contributions.