Health is a very competitive niche in the USA as well as over the world. Yet, it lacks a nice minimal full-functioned social media platform devoted to health-related discussion. Probody was born to serve the demand.
Developing a social networking platform in a CMS like Wordpress is nearly hard to impossible while the cost is pretty high. Meanwhile, programming the site in a specific language like PHP is not an ideal solution, in terms of content management, and ease of use. That's why Drupal wins the game with its extendability and a great content management dashboard.