This makes me think about the importance of being able to separate the content of a message from the presentation. I wonder how much better off we'd be if everyone was just able to do that (or if we just took for granted that other people were sufficiently discerning). The throw away marketing is still just throw away marketing no matter how much highlighter there is on it, unless it actually happened to be relevant in the first place. In which case what point was there to the attempt at persuasion?
In the act of perceiving a message, it is impossible to separate the factual content from the presentation. At that moment, subconscious effects have already taken hold. Even conscious thought struggles to counteract that. The only really effective means is to have a prior, well-defined decision process to prevent yourself from rationalizing a subconscious decision. Even if the wording was completely objective and factual, I could still persuade by selecting which information to include, the ordering of facts, the phrasing, and even which particular, yet still objective, words I chose. In any message, influencing the recipient's perception of content through its presentation is actually unavoidable. Hence, the attempt at persuasion. Your perception of relevance could very well be subconsciously influenced from slightly "slightly irrelevant" to "relevant" by such small changes. Each marginal shift leading from a "no" to a "yes" would show up as small but relatively large changes in response rate. An increase from 0.5% to 0.75% would represent a 50% improvement in campaign performance.