Not massive benefits by any means. Replaces this:

    def self.included(base)
        base.class_eval do
          validate :strong_enough_password?, :if => :password_required?
        end
    end

with:

    extend ActiveSupport::Concern

    included do
      validate :strong_enough_password?, :if => :password_required?
    end

One could possibly argue its a bit more consistent with the rest of the code-base, but thats a stretch.