Yesterday I participated in a meeting at a client's office where six people sat in a small conference room reviewing the contents of a PowerPoint presentation they are to deliver in a few days, and it struck me how exactly alike are PowerPoint and Wikipedia, the grassroots encyclopedia that anyone can contribute to. Well, they're alike at least in this one regard: Having to work together on a single page forces people to override their personal interests in favor of their shared values. At Wikipedia, that value is achieving a neutral point of view. At the business meeting, it was clarity and persuasiveness.
Of course, at the in-person meeting, the social structure inevitably gets in the way: The junior person doesn't push too hard and the senior person doesn't have to. I wonder how different the PowerPoints would have turned out if they'd been created in an environment where anyone in the group could comment on them or edit them anonymously.