Web Design Ledger (WDL) has a short article on including a social component within the design of a website to encourage visitor interactions.
Social web 2.0 trends have taken over many of our modern static websites. Nowadays it’s difficult to find a company who isn’t on Facebook or Twitter or Foursquare, or any of the other increasingly popular social networks. It’s important to consider this experience and how you can portray social connection in the eyes of your visitors.
Optimizing your Website for Social User Experience