We currently have the ability to attach comments to any CMS page using IntenseDebate or Disqus and we have plans still for an internal comment system which has not been completed.
However, as mentioned on our About page, mojoPortal is not designed with the goal to build the next Facebook or social networking site. The user profile page in mojoPortal is not designed as a tool for users to express themselves as it is in Facebook and it is not a goal for this project to make it like that. You could build your own custom features for those purposes but that is not a direction where this project is going. Our purpose is to build business web sites with social features but not to build social networking sites.
You could let users link to their Facebook page from the mojoPortal profile page.
We do plan a private message system where users can send each other messages, but not planning a wall for posting messages.