A blog, is quickly becoming subculture in itself. Like email and message board signatures, you can leave behind a personalized link to your site on various blogs. Also, make friends with bloggers who blog about the subject of your site. You can seek them out and offer to exchange links. This is also part of link-building.
Most blogs will allow you to hyperlink your name to any site when you leave a comment on a blog entry. By finding popular blogs that are related to your site and leaving an interesting comment, you will pique the interest of others, thus encouraging them to click on your hyperlinked name.
Another option is to actually run your own blog on a topic related to your wiki. If your blog gains a decent amount of readers and you are linked to your Wetpaint site, a viral effect occurs, feeding both sites' traffic.