How to build a Drupal-based forum/website that is def. anynymous?

Hi community! I am about to build a drupal-based forum or website, where people can report / discuss and  (auth. users) blog their experiences with mental illnesses – a facebook-like self-help group, where all the users can share their experiences, connect with each other and auth. authors write blog entiries. I know how to set up such a site using drupal, but I am not experienced with those “privacy” things – it is possible to set up such a site with keeping all(!!!!) individual-related information really(!!!) anonymous????