How Has Google's Mobile Friendly Update Affected Websites?

Last week, Google started rolling out a new mobile friendly update to its mobile search algorithm. This was aimed at significantly changing the mobile search results to give preference to mobile ready web sites over non mobile ready ones. Experts jokingly termed it 'Mobilegeddon', because all signs indicated that it is a major change in many years, and will significantly impact websites. But a week after the launch, has it really been such a significant update?