Web 2.0 basics
"The Web 2.0 lesson: leverage customer-self service and algorithmic data management to reach out the entire web, to the edges and not just the center, to the long tail and not just the head. Network effects from user contributions are the key to market dominance in the Web 2.0 era."
In my humble opinion, there's a real danger for almost every online content and commerce site that doesn't start integrating the above concepts to their services. Community-generated content and self-service underpins a virtuous cycle of increasing interaction and activity on a content or commerce site that establishes a meaningful social network. Consider that every additional community member at that point (having contributed content to a site easily accessible cross-platform to other potential members) becomes an evangelist and marketer for said content/commerce site to their own personal network, acting as a multiplier for viral user acquisition. Again, this isn't social networking for the sake of social networking. Instead it's a means of tying users/buyers into the fabric of a site which establishes greater trust to the content or service offered by the underlying application and driving increased activity as a result.
Umm that was a mouthful :(