Wikipedia authorship visualizationWhen Wikipedia (an online encyclopedia that anyone can edit) first began, some feared that it would be "a recipe for authorial anarchy" or that the "Internet lunatics [would] stumble upon [it]," (both from this NYTimes article), but it has pluckily proven that, in some settings, people with disparate opinions of the truth can reach a neutral consensus. Just as fascinating as the articles themselves is the process of authorship: the constant revision, vandalism, and contention that anneal these articles. Wikipedia offers a tabular revision history, along with "talk" pages for content discussion, but an impression of the overall motion of this collaborative animal is more elusive.
Fernanda Viégas, Martin Wattenberg, and Kushal Dave astounded a packed CHI session last Thursday with their extremely elegant history flow visualization tool. Entry persistence, additions, and deletions are color-coded by author, and can be spaced equally or over time. Anonymous contributors are gray. Mass deletions (such as when the Microsoft entry was replaced with "sucks") appear as solid black lines, and are generally repaired by other Wikipedians within two minutes. (Perhaps someone was going through a bad breakup when he deleted the "Love" entry). My favorite is the zigzag pattern from "edit wars" (see page 6 of Viégas's paper). In this image, two people battled over whether a "chocolate coulage" was a real thing, and you can almost hear them saying, "Nuh uh!" "Ya huh!"
On a related note, my UNC friends, Abe Crystal and Jesse Wilbur are devising system ("Who's My Daddy?" pdf) for wiki content authors to provide hierarchical information, as well. (Wikipedia doesn't allow people to create subpages in the main encyclopedia, but user-contributed structure would be really helpful in other wikis.) In this system, users vote on the best "parent" for a given page, and the one with the most votes appears in the breadcrumbs at the top. While a single-parent hierarchy might not be applicable in all wikis, it's a good start to the concept of distributed information architecture. The boys also get bonus points for their use of acronyms.