I fairly frequently get asked why the ProjectForum site isn't up-front in saying that it's a 'wiki'. Here are some of the reasons behind that.
First, for a substantial part of the target audience, the term wiki is meaningless, so a site talking about why ProjectForum is the best wiki (etc.) wouldn't be a great help. Talking about a forum where people can collaborate etc. may be a bit muddier, but a broader audience can get it. Besides, it takes people who are familiar with wiki about ten seconds to conclude there's some commonality there.
Second, I don't think that 'wiki' is a positive association for a substantial portion of people that know the term. Most wiki's are not very good, are very tech-centered, complex to use (to say nothing of installation, etc.). The audience for ProjectForum is fairly broad, and not overly tech-centered. I think the experience for users is substantially better than they're likely to have encountered previously in a wiki ("that confusing ugly thing where anyone could go in and delete all my stuff").
On that note, just as many very tech-centered people would rather spend a day or two hacking to setup a complex but free wiki that has less power and is more awkward than spend a couple hundred bucks on a (IMHO) full-featured, professional, documented, supported and easy-to-use package that they can get running in minutes, and will stay running with no hassles. Again, the 'I'm not paying a cent for software' crowd don't make an attractive market.
Another very big reason is that I don't see ProjectForum as a wiki as much as a general collaboration space. I can see it evolving in lots of ways that go well beyond the traditional notion of wiki. Things like real-time fit into my notion of what ProjectForum could become. I don't want to be restricted or pigeon-holed by 'this is what a wiki is' nor do I want to get caught up in implementing irrelevant features because 'wiki systems are supposed to have feature X'. Ultimately, it's the users and the uses driving it, not the technology.
Having said all that, I'm obviously very interested in attracting people who know about wiki software already. It's an easier sell, particularly to those who've tried to setup and use other systems, and gotten frustrated by the limitations. They like the idea, but want something better. This group in fact makes up a very substantial portion of our customer base.
These people do find us (in fact, they're normally quite motivated to do so!). We often mention wiki in notices of new releases to software sites, the term wiki is included in our site meta-tags, and we get a lot of traffic from search engine ads (e.g. via Google, Overture) that appear when people search for terms like 'wiki'. These direct to pages that draw direct comparisons with traditional wiki software.
So while there's definitely some advantages to more closely attaching a (to some) familiar term to ProjectForum, there are certain drawbacks as well. This continues to fluctuate over time. Anyway, enough for now. I'll have more to say on positioning etc. soon.