Today’s the day – our wiki is being migrated to MediaWiki. The old “moin” wiki is now read-only (and will remain so, at least for a few months), and is available on oldwiki.musicbrainz.org. The new wiki, once all the data has been migrated across, will be at the usual address.
As soon as the migration is complete, I’ll switch wiki.musicbrainz.org over to point to MediaWiki.
Unfortunately it won’t be possible to also migrate the user accounts from moin to mediawiki, so regrettably this means that once mediawiki us up, you’ll have to re-create your accounts. Sorry about that.
Update: the switch has been made – if you have any questions to ask or problems to report about this, please see the WikiMigration page. Thanks!
MetaBrainz Blog 
that’s cool, I think the MediaWiki is much better
Hi, I noticed that it is impossible to edit pages without being logged into the new wiki.
I would recommend to open the wiki to anonymous users again. Requiring a login raises the barrier for participation which is quite harmful from a social perspective. You should only do this as a last resort if you alredy suffer from massive spamming or trolling. I do not think this is currently the case and I suppose that MediaWiki has quite powerful spam protection and despamming features which can be used instead.
Sorry for ranting again but the new recent changes page is difficult to read and to use in comparision with the plain simple (not overloaded) old recent changes page.
But thank you for taking care of the wiki. 🙂