It is according to the New World Notes blog. Blogger, W. James Au, believes that until now, SL as a 3D wiki has merely been an analogy. He states,
"Virtual/real world architects Keystone Bouchard (Ryan Schultz) and Theory Shaw (Jon Brouchoud) of Wikitecture Studio have just filled this gap. Their "Wikitecture Tree" saves the data of a building project into a leaf on the tree. Collaborators can then review and critique each, and if they like, create a new version of it-- which then literally becomes, in turn, another leaf sprouting from the original design. To see any of these iterations, you just click on the leaf, and the design rezzes before your eyes."
A demo of Bouchard and Shaw's Wikitecture Tree is available on YouTube at http://youtube.com/watch?v=Z3eWKIJxzyc .