IT IS the biggest encyclopedia in history and the most successful example of “user-generated content” on the internet, with over 9m articles in 250 languages contributed by volunteers collaborating online. But Wikipedia is facing an identity crisis as it is torn between two alternative futures. It can either strive to encompass every aspect of human knowledge, no matter how trivial; or it can adopt a more stringent editorial policy and ban articles on trivial subjects, in the hope that this will enhance its reputation as a trustworthy and credible reference source. These two conflicting visions are at the heart of a bitter struggle inside Wikipedia between “inclusionists”, who believe that applying strict editorial criteria will dampen contributors' enthusiasm for the project, and “deletionists” who argue that Wikipedia should be more cautious and selective about its entries.