What does the CiviCRM Contact Reference Field Drupal module do?
This module functions as a type of Entity Reference field so that you can link Drupal entities back to Contacts in Civi.

In the display settings for your content type, you can specify whether the Civi Contact appears as:


a plain text name,
their name linking to the Contact's record or
a raw Contact ID (CID).


An example of how we use them:

We have a Drupal content type called Event.  We want staff to know who is leading the event so we include a CiviCRM Contact Reference field.  When the Event node is filled out, we choose the event leader from a Civi-linked autocomplete field.  When the node is saved and displayed, the Civi Contact Reference field displays the event leader's or leaders' name(s) so the staff person can just click on the name to go straight to the individual's contact information.