In short and simple terms, the word "dang" is a mild exclamation used to express surprise, frustration, or emphasis.
Sentences with «dang»
I just finished our nursery using polka dot fabric, so I'm a little partial, but it is just so dang pretty on the walls like that. (notjustahousewife.net)
This game looks pretty dang good for a racer with impressive looking cars and a very interactive environments. (playstationlifestyle.net)
There's something just so dang good about fresh - picked strawberries that will never, ever match up to grocery store berries. (doughseedough.net)