Using Twitter for OAuth 2.0 is just a first step into the IndieWeb. IndieAuth can technically support all sorts of login options (emails, mobile login, passwords, etc) @manton has expressed that he has plans for deeper IndieAuth integration in micro.blog, and David Shanske is currently working on an IndieAuth plug-in for WordPress that will allow the use of the Wordpress User/Pass to login to Quill and other Micropub clients