Wikipedia is an open encyclopedia that anyone can edit. As Doc Searls recently put it, Wikipedia is, like the protocols of the Net, “a set of agreements”. A Web protocol defines the way in which computers communicate with each other and make decisions to ensure successful transactions. Wikipedia policies have the same purpose, but instead of transactions between machines, they regulate human decisions. An important part of these decisions bear on what topics are suitable for inclusion in Wikipedia and what topics are not. As any writer knows, this is perhaps the most delicate editorial issue ever. The present project looks into the nature and shape of collective decisions about the inclusion of a topic in Wikipedia.