Anarcopedia
The Anarchopedia .org is the first large public wiki to attempt to eliminate all sysop vandalism.
It's original stated goal was to let any user undelete pages, making ad hominem delete no worse a problem than ad hominem revert. Without this special power to prevent their opponents from reading the alternative view, it is thought, sysop power structure will not form at all. Apparently it has not lived up to this goal fully.
The Anarchopedia's policy effort builds on prior efforts at Recyclopedia - an attempt to build a large public wiki without use of sysop powers at all.
By contrast, Anarchopedia seems not only to embrace but seek to extend the NTPOV to all aspects of wiki governance and wiki management. There are no vile mailing lists and no cabal of friends with infrastructure owners trust as there is at Wikipedia.
It is also notable for embracing a one wiki model. It has some problems addressing language vs. area specializations.