  Information-communication technology promotes collaborative environments like
Wikipedia where, however, controversiality and conflicts can appear. To
describe the rise, persistence, and resolution of such conflicts we devise an
extended opinion dynamics model where agents with different opinions perform a
single task to make a consensual product. As a function of the convergence
parameter describing the influence of the product on the agents, the model
shows spontaneous symmetry breaking of the final consensus opinion represented
by the medium. In the case when agents are replaced with new ones at a certain
rate, a transition from mainly consensus to a perpetual conflict occurs, which
is in qualitative agreement with the scenarios observed in Wikipedia.
