I am planning to implement the openid and oAuth in Erlang. There are couple of modules already there which I am going to look into however I am interested in Attribute exchange and policy extension for multi factor authentication. Current incarnation of openid has UX (User experience) issue due to URL redirections. It is addressed in Openid UI extension, So possibly the popup based solution would come into practice.
I will update this post when I figure out the issues and possible solutions.
I am interested in oAuth enforcing standard mechanism to share different resources (http).