Recently, CommonPlaces presented a conference on 'Reduce the Cost of Each New Website With Drupal Multi-Site"
Drupal’s elegant multi-site capabilities give businesses a repeatable framework on which to run many websites from a single installation of Drupal—enabling centralized system management while reducing the incremental cost of additional websites to almost zero. The benefits of multi-site include streamlined maintenance, lower operational costs, and the ability to target market segments in a more controlled way.


