Web Persuasion — Power and Responsibility
A web site that doesn’t persuade is a failure. Your web site can’t sell skin care products, convince people global warming exists, win people over to your parenting methods, or encourage women to get mammograms without using some techniques of persuasion.
Since it’s so pervasive, we should take a look at the different persuasive techniques available to us.
Appealing to Intellect and Reason
The central route to persuasion
When you write content that you intend people to carefully read and really think about, you are depending on a central route to persuasion. Sites like these use statistics, rationality, logical arguments, expert testimonials, and infographics.
Some examples of sites that rely heavily on central routes to persuasion are LetsMove.gov and SkepticalScience.com.
Credible sources are more likely to lead to attitude or behavior change immediately after the information is presented. This is why DermaDoctor offers dozens of very detailed and informative articles, but fills them with links to their products which provide opportunity to act on the information.
Sleeper Effect
Unfortunately, the claims of less credible sources will actually increase in persuasiveness over time and the potency of credible sources decrease. This is called the sleeper effect and it happens as the people who’ve read the content separate it from its original source. As the weeks go by, they forget whether or not it was trustworthy but just remember the general content.
It’s easy to see, then, why there is more to persuasion than high quality information.
Appealing to Emotion and Instinct
The peripheral route to persuasion
GoDaddy does not use videos and photos of Danica Patrick and Jillian Michaels because they are experts on domain name services. Bob Parsons knows that including their visages on the site will be persuasive because people will make decisions based on influential cues that aren’t really relevant. This is called the peripheral route to persuasion.
Credibility
Using the mere presence of a credible figure increases the perception of trust and persuasiveness. Credibility means different things to different audiences – it can be celebrity, a professional appearance (e.g. someone in a lab coat), a certain level of education, etc.
Each site below makes a different assumption about what credibility is:
GNC

Would these doctor endorsements persuade you to buy from GNC?
Proactive

Who would care more about acne than a celebrity?
Let’s Move
Attractiveness, Likability, and Similarity
Several studies have found that attractive people are more successful in influencing the attitudes and actions of others than less attractive people. The same is true of people who are perceived as likable and similar to ourselves. We gauge similarity by attitudes, background, values, and appearance.
The Ladders
TheLadders.com uses credibility on its home page, but it also leads with attractive, likable, professional individuals who probably appear similar to The Ladder’s target audience. Even if those individuals aren’t actual employees, they make the company seem approachable and caring. Of course, we don’t know if these are honest claims until we’ve paid for their service.

These friendly, attractive people can't wait to help you!
Chantix
Chantix is a drug used for smoking cessation. Instead of leading with facts and figures about the dangers of smoking, they have created a site that uses very effective video stories. The stories are told by various people who were doubtless chosen based on their similarity to different segments of the Chantix target audience.

Chantix uses video stories that their audience can relate to
Vividness and Fear
Vivid and sometimes fear-inducing imagery or copy can be very persuasive, especially when paired with clear actions that can be taken after the information is consumed.
Consider the Unsweetened Truth campaign, which clearly depicts the worst results of heavy tobacco use. They don’t follow up with clear actions someone could take after consuming this disturbing imagery, which would maximize the effectiveness of this technique.

Vivid imagery induces smoking-related fear.
Responsible Persuasion
As you’ve probably noticed, persuasion almost always includes some tactics from both the central and peripheral routes. In fact, the most successful sites bring all of these tenets together to really make an impact.
Consider DoSomething.org, which combines a large amount of fairly well-organized and helpful information, likability/similarity, vivid imagery, clear actionable items, celebrity endorsements, and social influence.
The word “persuasion” can come with baggage and be a synonym for manipulation. That’s why it’s important to be armed with a knowledge about how our sites may be influencing others, so we can make responsible and well-informed decisions about how best to employ these techniques.