It seems like everybody under the sun is putting together a wiki for something. There’s even a wiki for the board game Go. But with all these wikis around, is a wiki always the best tool for the job?

Back in September of last year, I talked about some general questions people should ask before setting up a wiki. The very first question I asked was: “is a wiki the best technology for what I am seeking to accomplish?”. That may not always be an easy question to answer.

So if you’re thinking of setting up a collaborative space — when should you use a forum and when should you use a wiki?

Well, let’s look at the purpose behind each of the tools first. Wikis are designed to get a group of people to document their agreement on a set of facts (as I pointed out in the third and fourth questions in my previous post, i.e. “am I asking my community to create a universal truth based on tangible facts?” and “is my community going to be able to agree on these facts?”). So wikis are great for laying out basic facts where we don’t really care how we got to the answer.

Forums, however, are much better at outlining the iterative processes that allow us to get to an answer. We don’t really care how the person who wrote a Wikipedia entry on Ecuador found out that Quito is the country’s capital — we just want to take a look at the page, get the fact we need and move on (please note that I’m not arguing that Wikipedia is always 100% accurate… ) .

Forums are a different beast. Imagine if I’m trying to figure out something more complex and specific, like trying to figure out what I can deduct on my taxes or trying to figure out why my installation of Microsoft Word keeps crashing.

Let’s take the example of Microsoft Word a bit further in order to illustrate this. It would be nearly impossible to predict every possible combination of hardware and software someone could have on or in a computer — making a wiki the lesser tool in this case. In the case of a forum, I can easily post all the hardware and software I have installed, and get an answer from someone who may know something I don’t about my particular configuration.

But forums are also useful in another way. They also allow other users to search for that example and see the iterative process that happened in order to get to the answer (like “did you try rebooting… uninstalling and reinstalling Word… checking for viruses?”). You can quickly discard all the failed steps and close in on the right answer.

Forums also have another big advantage over wikis, and that’s in the human interaction component. In our previous example, someone might suggest uninstalling and reinstalling Word as a solution, only to have someone else say “I already tried that” — which quickly rules out that potential solution. Wikis don’t provide a means for direct communication between users.

It’s not that wikis aren’t a great tool — it’s just that we always have to keep in mind that they are impersonal, general and non-iterative. Forums however, lack the clear consensus-building (OK, sometimes it’s more grumbling acceptance rather than consensus) capabilities of a wiki.