It looks like Fast Company is using Drupal to power this site. Pretty sweet. I use Drupal to power my site as well. It seems more and more traditional (and new age) media brands are building communities around their core brands.

On the upside they get

• free content
• frequent visits
• user loyalty

On the downside

• spam (maybe not today but eventually)
• a lot of content that needs policed
• a lot of watered down content (after all, what incentive is there for a well known expert who owns their own site to post their content on a third party site that anyone can join?)

This sort of blend of authority + user generated content is going to wreak havok with search engine relevancy algorithms. In fact, it has already rendered Yahoo! Search useless for a lot of search queries.