OpenID

OpenID is an open, decentralized, free framework for user-centric digital identity.

Benifits to an OpenID auth system

For something like the Gnoem wiki, or Bugzilla, OpenID is perfect, as while a majority of the content comes from dedicated contributers with accounts, there are also 'one stop' customers who don't want to take that time just to leave a short comment.

Implementation

There is a plugin for MoinMoin, so it should be pretty easy.

http://moinmoin.wikiwikiweb.de/FeatureRequests/OpenIDSupport