From TDWG Terms Wiki
The OpenID extension for MediaWiki allows you to login using your OpenID username. We have started to evaluate to include this extension here for this Vocabulary Wiki.
Chances are that you already have an OpenID:
- See also: http://openid.net/get-an-openid/
- MyOpenID: http://username.myopenid.com/ 
- Google Profile URL: http://google.com/profiles/me
- Blogger URL: "blogname.blogspot.com"
- flickr: use your photostream URL as username: http://www.flickr.com/photos/username/
- WordPress: “username.wordpress.com"
- Download at http://www.mediawiki.org/wiki/Extension:OpenID
- Unpack OpenID to the extensions folder of the MediaWiki
- cd $IP/extensions/OpenID an run "make" to download library and patch PHP 5.3 or later.
- Modify LocalSettings.php, add: "require_once( "$IP/extensions/OpenID/OpenID.php" );"
- cd $IP/maintenance and run "php update.php" to add OpenID tables to the MediaWiki database
Note: If you restrict general access to wiki pages, you must add anonymous access for Special:OpenIDLogin and Special:OpenIDFinish or the OpenID Verification will fail. Typically this is done by adding those pages to $wgWhitelistRead in LocalSettings.php.