Check it out, no the whole world doesn't observe daylights saving time, but most of it does.
And it is observed in the US, except for in the Hawaii, Arizona, and Indiannapolis (kind-a), in metromolitan areas, so scharatz's friend is kinda-right.
About 70 countries around the world observe DST in some form. Here are some interesting facts about some of them:
In Canada, every province except Saskatchewan observes DST. It remains on standard time all year long.
It wasn't until 1996 that our NAFTA neighbors in Mexico adopted DST. Now all three Mexican time zones are on the same schedule as the United States.
Also in 1996, members of the European Union agreed to observe a "summer-time period" from the last Sunday in March to the last Sunday in October.
In the winter months, Russia, which spans over 11 time zones, is always one hour ahead of standard time. In the summer, Russians turn their clocks ahead one more hour.
Most countries near the equator don't deviate from standard time.
In the Southern Hemisphere, where summer arrives in what we in the Northern Hemisphere consider the winter months, DST is observed from late October to late March.
Three large regions in Australia do not participate in DST. Western Australia, the Northern Territory, and Queensland stay on standard time all year. The remaining south-central and southeastern sections of the continent (which is where Sydney and Melbourne are found) make the switch. This results in both vertical and horizontal time zones Down Under during the summer months
China, which spans five time zones, is always eight hours ahead of Greenwich Mean Time and it does not observe DST.
There is no DST period in Japan either.