My good friend Carlos asked me a question about wikis - he has a problem because there was some inaccurate information in a third-party article about his company, and he was looking for advice. Warning: If you haven't checked out your company or products and services in Wikipedia, do it immediately! Until challenged, whatever is written there stands as fact.
You should understand the Wikipedia contribution policy: "Visitors do not need specialized qualifications to contribute, since their primary role is to write articles that cover existing knowledge [...] Most of the articles can be edited by anyone with access to the Internet [...]Anyone is welcome to add information, cross-references or citations, as long as they do so within Wikipedia's editing policies and to an appropriate standard. Substandard or disputed information is subject to removal." [Emphasis added]
Huh!? This means anyone can contribute content, and that Wikipedia does not check for veracity. That's up to the users. Wikipedia's editors will sometimes act to remove disputed facts or errors-in-fact when they are notified.
So my first recommendation is to have some-one go into Wikipedia and correct any inaccurate information via the editing tool. It is important to only correct factual errors - otherwise you will attract attention and negative comment.
Second - you should consider creating an alternative entry if there is a reasonable case for doing so. Again, be careful to report facts ("only the facts, Ma'am..."). When people search Wikipedia, they will then see both entries.
Next, invite your advocates to contribute to your wiki entry. The point of social information resources like Wikipedia - after the obvious information resource use - is to have fact-driven conversations where a variety of users can explore a variety of avenues about the topic at hand. If you have a reasonably complex offering, consider posting your FAQs as part of the content. On the other hand, you might want to use the collaborative nature of this tool to have customers help one another get best use from the item.
Finally, consider setting up another wiki of your own: for employees and your downstream sales force. This wiki should focus on capturing the "unwritten" knowledge all throughout your company - and listening to this conversation may just provide a few tips on where to take your products or services next!
That's all you get for free! Contact me if you have similar questions to Carlos, and I'll try to help you get maximum leverage from the social media jungle.