secondary site

We are looking into creating a secondary site that would be segregated from our principle newspaper website so that we can allow community users to create their own blogs and add comments.

The idea is that in doing so, we can better protect the newspaper's brand.

The question is though, should we do this as a Drupal multi-site configuration, as a standalone Drupal install or, for simplicity, use Wordpress instead?

The Wordpress option is based on the assumption that users are only going to be blogging, but there is a remote possibility that these functions could be extended.