Summary
This quote suggests that advertising is a noisy and attention-grabbing tactic that is used to sell products or ideas, much like the sound of a stick rattling inside a swill bucket. It implies that advertising can sometimes be seen as a disruptive or obnoxious approach that attempts to capture people's attention by making a lot of noise. This metaphor highlights the inherent loudness and lack of subtlety in advertising's attempts to persuade and influence consumer behavior.