I found a very detailed and positive review of Drupal [1], which you may want to read to better understand the application, its roll in our social network, and why we chose Drupal over all other options - public and private
Links:
[1] http://www.businessblogconsulting.com/2004/09/drupal_blog_pub.html
[2] http://realneo.us/content/dan-gillmor-moves-drupal-bayosphere
[3] http://realneo.us/news/2005/01/20/happy-birthday-drupal
[4] http://realneo.us/realneo-topsoil-technology-optimization-platform-for-social-organization-innovation-and-learning/realneo-development-plan/names-