In the site that I've joined, people are busy greeting each others for Mother's Day! But it's different here in Korea because it's not Mother's Day but Parent's Day. It is a day for Mom and Dad. It's a holiday here. It marks red on the calendar. Fortunately, it's Sunday this year so it has the same day in America and any other countries. Parent's Day is celebrated every 8th day of May every year but people are busy buying gifts, carnation flowers, cakes or going to the restaurants the day before the celebration. In Korea, it's better to do it in advance so it confused me on my first consecutive years here in Korea.
In Korea, giving carnations and cash is the best presents for parents. Koreans specially in laws love receiving cash rather than any other gifts.