I love the fact that their work environment is not limited to their desk and meeting rooms. You can select the environment that works the best for you, and that stimulates the qualities you require for a specific task (or just pick the one you like the most).
Though many dot-com and ad agencies may make their offices look like adult day-care, I think the underlying ideas at play are the future:
* Physically and emotionally warm environments
* huddle spaces for face-to-face collaboration
* low ceilings create a quiet conference and intimacy
But for other parts of business (research, email, document editing, etc) I have found the war-rooms and coffee-shops to be a better fit.