I think I may have found Claire Fontaine’s cousin!
Wu Ming. They were initially a group that used the Luther Blissett nom de plome to write an anarcho-syndicalist novel and manifesto, later creating a new collective identity to continue their work.
Here’s a funny video introduction:
For more background info, check out the wiki page http://en.wikipedia.org/wiki/Wu_Ming
They have written a ton of stuff (http://www.wumingfoundation.com/italiano/downloads.shtml). A recent critique of summit protests has been making the rounds (also published as the preface to the Verso Revolution series book on Luther- http://www.wumingfoundation.com/english/wumingblog/?p=1014
Of personal interest appear to be their satire of primitivism Guerra agli Umani (War on the Humans). Too bad it’s only in Italian and French.