The Hidden Nerve
We speak of a person or an issue "striking a nerve" with an audience. The most powerful version of that occurs when the audience member doesn't necessarily know that there is a nerve to be struck or perhaps feels isolated, suspecting that he or she alone feels that way about a matter. When that connection between the speaker and the individual is made, it is powerful and will likely be lasting.
Surfacing a subject that everyone knows but no one mentions can be another moment of power. It should not be raised casually because the next question will be, "Now what?" The answer to that should not be squandered.