If you ever hear of someone speaking in a teleological manner, don't assume it is about cell phone etiquette. They are just expressing a philosophical approach to life's meaning and judgment about matters.
Telos is a Greek term that explains a thing's essential purpose or function. In philosophy this term is used by Aristotle (teleology) to explain objects in light of their intended aims or purposes.
When it comes to web design, approaching it according to its intended purpose saves a lot of time and money. Unfortunately web design is viewed as one of those necessary, and cost-effective, projects that promote an organization, service, or product. The problem with this approach is that it is often short-sighted. The resultant website might achieve some immediate concerns, but it will soon become apparent that bigger issues were never addressed. In some cases, these issues are compounded by its website design.
For instance, let's say XYZ company, who sells different types of widgets, realizes that one of their widgets isn't selling like it used to. Their target market views this particular widget as a low-end commodity. And yet a competitor is selling the same widget much better. This is because their widget is positioned better in the minds of the consumer.
To counteract this problem XYZ company decides to update their website to feature their widget more. They redesign their website to encourage more interest in this widget. And it works. More people are investigating their widget, and sales are even picking up momentum. But, what also happens is that the sales of XYZ's other items are beginning to drop. And public perception of XYZ company shifts. They are now perceived as makers of a cheap low-end widget, rather than makers of an assortment of valuable widgets.
The problem was not the website. But rather sustainable market growth. And that growth was tied to their brand more than to a particular product. XYZ company lost sight of the real problem. Their customer's perception. Instead of asking the website to solve a widget sales problem, they should of asked what the purpose of their site was in the first place, and the purpose of solving the sales problem. Everything following the answers to these questions would frame the solutions. In other words, they will be able to better position their website design strategy toward the website's intended objectives while increasing sales of their low-end widget.
The best approach to web design — or any other design, for that matter — is to design the item according to its intended purpose or essential function. The best way to increase sales of an item is to ask why it's necessary to increase sales of that item. That can lead to an effective design strategy. And a strategy is better than spending money to solve the wrong problem.