There is a reason that schools and businesses caution against using encyclopedia wikis for sourcing information. A wiki is a result of a collaboration of many people across the internet, all bringing small bits of research and input together to create a mostly accurate picture of whatever the topic of the wiki might be. For this reason a wiki holds incredible amounts of information, but is also subject to inaccuracies and biased viewpoints.
An online wiki is not like a world book online reference center or Encarta encyclopedia online. Articles created for those sites are done by professionals, subject to critical review, and are trusted to be 100 percent accurate. That is not to say that wiki websites are not useful. There are scores of wiki sites out there covering everything from computers, video games, biology, science fiction, and DIY. For the most part the information they present can be trusted.
Depending on the wiki websites you frequent, there may be a formal process you have to go through before you can create a wiki article to add to their site. However, in most cases, these sites make it as easy as possible for other people to create wiki pages, because the more contributors there are then the more information becomes available. If just supporting an existing wiki is not enough, or if you see a place where a wiki does not yet exist, but could be useful, then you can create your own wiki site!
Step 1. Decide on the content.
The very first thing you should do is make sure that the wiki you want to create is not already in existence. If it is not, then ask yourself if there are enough people out there with an interest in your topic. If the answer is yes, proceed to step two.
Step 2. Select Wiki software and hosting services.
Try investigating MediaWiki, Wikia, Wikispaces, and Wikidot for starters, but there are other wiki creation tools out there as well. Once you have selected a software that you are comfortable with, and you have found a way to host it, then you are ready to start building the wiki.
Step 3. Collaborate!
Let others know that you have started a wiki and ask them to contribute. A wiki is only as strong as its contributions, so it is in your best interest to get experts on your selected topic to give their input to articles and pages. Remember that you will need to check pages for mistakes and errors.
Wiki websites are extremely helpful tools, so creating your own is a great way to add information to the internet. As a bonus, you will find other individuals who care about your choice of topic, and you will build a community.