We present a model of the collaborative process of document authoring that takes place in the free online encyclopedia Wikipedia. We consider the process of editing of a Wikipedia page by a group of agents with different opinions (points of view on the topic of the page), which are continuous variables, coupled with a time-inhomogeneous process for the WWW browsing to the page, in which motivational factors for the participation to the collaborative process affect the rate of visits to the page. The model of editing takes inspiration from response models of biological neurons. Social interactions between agents are thus mediated by the content of the page. In this original context of opinion dynamics, editors and regular users of Wikipedia are seen as actors having different objectives about what the point of view expressed by a Wikipedia page should be like, and modify it using a simple greedy heuristic. Interesting phenomena like the emergence of a shared, neutral point view may then be cast in the light of this dynamics of opinions. When the model of opinion dynamics is considered in isolation, simulations show that agents with opinions and rates of activity that are fixed in time converge on a pages opinion that reflect, on average, a shared point of view between.