Persuability is the art of turning your visitors into customers. The theory says that the more persuasive is your product the more easily it will be sold (with notes, but enough for now).

From the usability approach we can think in persuability as a way of creating passionate and highly interested users. Being persuasive, we can enhance better user experiences in a positive and happy context or more convincing, at least. But, what if we don't want to persuade? What if the main goal is to dissuade users?

I have been looking for an answer in literature without success, so I'm going to ramble to see what happens (obviously, any resource or idea is welcome). To dissuade users from doing something (can we call it dissuadibility?) could be useful in a service application.

Hope this is good example: we have an e-commerce and we want to provide three options of buying a product, e.g. buying online with registration, buying online without registration and ordering it and pick it up on the physical shop.

Here we have different purposes; one is to offer to the user many choices to look like the perfect and suitable service. Other one could be to increase online sales because it has lower costs; but if we have a commerce we really want to sell the more, we need to know who our customers are, so we will need they have been registered in our online store.

For the second purpose we will want to persuade them to buy online with registration as we want to dissuade them to buy online without registration. Though this last way is rather than just ordering.

How can we get it? Well, first we need to make use of visual aid to support our favourite message: get registered, please. Besides, we need to communicate and increase user expectative using arguments: he only will register if he gets a benefit.

Secondly, we do not want users think that buy without registration is the best choice, but reducing the font-size is not a option, is it? One solution could be hide that option behind a beautiful link labelled "Other buying ways" next to/under the registration box.

I guess it has pros and cons, but it is not just a matter of getting things done, but a question of we want to communicate/suggest/persuade/dissuade users our preferences.

A good blog to know more about persuability: http://persuabilidad.com