gdth
"gdth" means "good to hear" in which the person who is using this abbreviation is trying to provide a nice and respectful response.
Person 1: "Hey how was your day Person 2!"
Person 2: "Oh it was great! I got a full ride scholarship to HARVARD! MY DREAM SCHOOL"
Person 1: "Omg lucky! That's gdth"
Person 2: "Oh it was great! I got a full ride scholarship to HARVARD! MY DREAM SCHOOL"
Person 1: "Omg lucky! That's gdth"