Much like the US celebrates Labor Day in September instead of May Day on May 1st to celebrate the labor struggle (and the Haymarket Massacre), the US ignores International Women's Day in favor of Mother's Day. You think of Mother's Day now as a fake, Hallmark holiday, but in actuality, it has radical routes, founded by women who saw great tragedy in being asked to raise and nurture generations of cannon-fodder.
My friend Jenya, who unfortunately I haven't seen in ages, told me that as a child in Russia, Women's Day was a national holiday and that people would bring gifts to female family members, maybe only their mothers. I cannot recall.
Women's Day is an international holiday, recognized by the UN, which commemorates women's struggles for suffrage and equality. Remember that women have had the right to vote in the Unites States for less than a hundred years. The sacrifices and struggle made by our foremothers to win this right deserves celebration. We must honor those who in the past struggled for freedom and we must never forget that our freedom is hard-won. The UN has a webpage explaining the history of this holiday. Like so many struggles for equality, it has strong socialist roots. Probably why we ignore it here, alas.