Social networking sites - Community sites

I am a master student from London South Bank University in the United Kingdom. I am doing a research on one specific aspect of Drupal.

In essence my study is about assessing ways in which Drupal can be used to provide various kind of social networking functions since it wasn't primarily designed for that purpose.

Please tell us how you think this great content managemnt system ( CMS) can also provide social networking capabilities (features).

In order to help us answer the above question it would be extremely helpful to have the views of Drupal users like yourself.