* How about same-time communication? E.g. I need to discuss things with my designer, oh wait, he's gardening at the moment, or he works at night.
* How do you know when to start/stop your day? E.g. In "normal" office, it's usually 9 to 5.
* How do you schedule projects? Fixed time simplifies scheduling ("This project is 5 man-days").
* Who pays for supporting equipments (desk, LCD, internet, nice coffee) if I work from home?
* Specific to 37signals: How did they make the video? Did the video guy traveled to each and every employee in the video to tape them?