However, if the model is easily talk backable, it will not have too much time to raise barriers that make the entrance in the market more difficult of other companies. These barriers also can be of exit for the clients, is to say that it is difficult to change to them of company once are had customary to use the services and the form to provide them with a certain company. And because it is a suplicio to terminate itself, like in most of telephone operators of our country, but because the value that provides a certain company to him so is not elevated that it would cost a time and effort to him that is not arranged to invest to obtain the same one with another competitor. It would be the case, for example, of the bookstore online Amazon. In his day, to the being first in attacking with force the sale market online of books, it was able to catch a good part of the consumers, who went accustoming to their system of order and its system of book recommendations based on the knowledge which they have of the client. If a client wants to change of bookstore and to have services such, she will cost a learning effort to him and she will have to spend a considerable time until obtaining the same value. Therefore, those that have come later, have had it enough more difficult.