Means, Thank you very Much
Domo Arogato, Waita-san
a phrase in the Japanese language that means "thank you very much". Made popular in Western culture by the 1983 hit "Mr. Roberto" (also known as "Kilroy Was Here", "The Modern Man" and "Domo Arigato, Mr. Roboto") by the band Styx. This is how many Americans learned the phrase.
after the Japanese man took a picture of me (sitting in two countries at the same time!) at the U.S. - Canada border mark on the Niagara Falls Peace Bridge I thanked him by saying "Domo arigato". He smiled and shook my hand.