Once in a blue moon, a data visualization comes along and wallops you with its brilliance. Case in point: "Notabilia," which shows the debates behind some of the most controversial Wikipedia entries.
Created by Moritz Stefaner, Dario Taraborelli, and Giovanni Luca Ciampaglia, it's surprisingly quite simple: Each strand in the tree you see above represents a single Wikipedia article that, after a long debate, was either kept or deleted. The colored segments represent the various arguments pro and con—green represents an argument to keep, while pink is an argument to delete.
Together, the strands show the 100 most debated entries. But here's where it gets really brilliant. Each green segment causes a strand to lean left a little; pink causes it to lean right. Thus, a Wikipedia entry that almost all the editors thought should be included ends up looking like this:
And the truly controversial entries look like this—much straighter, because the argument never had a chance to curl definitely towards either side:
Very few arguments curl across the middle. That is, few of them were swinging strong one way, only to be turned around by some decisive counterargument. But it does happen:
If the name Moritz Stefaner doesn't sound familiar, it should: He's the brilliant mind behind this remarkable visualization of why New Yorkers move into and out of the city, and this one, almost as clever, of Twitter conversations.