Simplicity
It is almost a philosophy to simplify once world. This simplification does not stop at technology. Let's make a step back. Do you have all the great buildings in your mind which were built a long time ago? Here is an example of a great building. Although it is not that old, it looks great and far away from beeing simple:
It's the city hall of munich which was built arround 1900 in nygotik style. There are lots of squiggled buildings all over the world craying out "I am complex, I have will power". The world turned and they buildt buildings like this one:
Its message is an other one: "I am different but controllable on a shoestring". Today, we try to demonstrate that we have everything under control. We hide the costs and try to show that the world is an easy one which is straight, uniform and accessible for all of us:
Is it horrible, isn't it?
It's the same which is observable in our interaction, too. We try to reduce the effort for an interaction to increase the outcome: the consumption. This Human-Machine-Interaction principle is called "Simplicity".
A computer has a really simple interface, it's just a buttom that you have to push (Yes, it's the beginngin of the 21th century and we still have to push buttons....). But simple interfaces are not essential for success. Imagine a car which has a horrible complex user interface. You have to open the door and you have to start the engine with a precise process. Driving a car is even more complex but nevertheless it's one of the most popular modern user interface on earth. (Note: driving itself is easy - driving in a social environment is not easy!).
Everyone can drive a car and no one would think about an alternative user interface. Isn't it a great customer retention, is it?
It would be one, but it becomes self-propelling and now it is prior art and everyone use it, which is obviously the worst case for every marketing department. There are many examples in marketing e.g. people in Germany often say "UHU" when they like to glue something together, independent which adhesive poduct they use. But "UHU" is the name of a manufacturer of adhesive products! It's the same for the brand "Tempo" which is often used as synonym for an handkerchief. Back to human machine interaction; There is growing evidence that gesture based user interfaces will become prior art. The result is dichotomous as the customer expect this kind of handling, the scope decreases for a company distinctive look and feel user interaction. This can adversely effect the company customer retention. Today, the human machine interaction is a significant part of a brand.
You should pay great attention to that topic!