DST makes no sense nearer the equator where there is less variation in daylight hours throughout the year. There goes much of Asia, Africa and Central America. It is popular with people in wealthy democracies which enjoy around an 8 hour working day and have a culture that values outside recreational time and people have a say in such things. That pretty much explains most of the map. Many of the places that don't have DST are between the tropics, poor or have no functional democracy. The rest are more concerned with getting a few more holes of golf in after work than the welfare of Microsoft's staff.
