Follow the sun refers to international teams. There are lots of ways to run teams scattered across various time zones, but the way I’ve found to be most effective is to let the work follow the sun.
Recently on my project most of the team went to events in Asia with me being left behind in Boise. At first I was upset on not being there with the team, but as I let my reality sink in I learned that if I had been there the project would have only had a 12 hour window to get work done in any 24 hour period. With me being on the other side of the globe we could use all 24 hours in a day as we needed to.
It didn’t happen that we needed to every day. But for the days we needed to it really helped us succeed as a team.