USFDCS promotes collecting First Day Cover: envelopes with the stamp cancellation from the city and date of the stamp's first issue. Colorful and topical cachets complement the stamp.
It's a bunch of stamp collectors who collect U.S. stamps that had been postmarked on the first day they were issued and freely sell and trade amongst themselves and other collectors.
The actual name is the American First Day Cover Society. They come with a special post mark date and a brief history of the significance of that particular stamp.
The FIRST and ONLY not-for-profit, non-commercial, International Society
devoted exclusively to First Day Covers and First Day Cover collecting.
Founded 1955.
The third largest philatelic organization in the United States
