The best example is Star Wars. Luke asks Ben Kenobi if he fought in the Clone Wars. Kenobi says yes, and then moves on with the plot. The characters knew what it meant and didn't talk about it at all after that. For years everyone speculated on what any of that meant. Clone wars? What was a clone? Were they good or bad? George Lucas engaged the imagination of his fans on so many levels.
As a reader. I LOVE icebergs in stories. Books, TV, Movies I can't have enough.
Another example of it is The Office. Creed Bratton says small things at just the right moments that it engages us further than just Jim, Pam, and Michael. His sayings are icebergs. We see the surface, but so much more is implied.
The following is the best. In 10 words we get what could be a whole movie.