OpenID

MediaWiki should operate as an OpenID consumer for people who have identities elsewhere and wish to link them to their MediaWiki accounts. Registration on MediaWiki is easy, but changing your password on many MediaWiki websites is not.

This would solve the problem of multiple logins across the gigantic Wikimedia network, among other things. Wikimedia could offer an OpenID server as well, if it wasn't too much of a bandwidth load.