As a result of the penetration of internet in the world and the availability of broadband, especially in developed countries, has been a three years a boom very large with software applications licensed under the On Demand model. There are many terms that the tech industry is using a similar concept. I think that what really achieve is to generate more confusion in the market. Basically this software usage model corresponds more to a service that a rental or leasing of software licenses. You hire a service that consists of having at their disposal the use of software and technology that supports it (servers, operational systems, data bases, etc.). CRM-specific disregards by the installation of new versions, of problems of system crashes, of staff of technical support and many other items associated with the operation and maintenance of internal information systems, in this case. Like any other model of use or licensing of software, it has its pros and cons.
This model On Demand, SaS (Software as a Services) or as they call it lately Cloud Computing or cloud computing, presents several disadvantages also, within which the most relevant are the fact that data are outside your organization, information is in the cloud and the processes of integration and customization are not as flexible as they can be in a traditional (with their servers operating modelsoftware, and data within your company). On Premise model refers to the traditional scheme of licensing and use of software, i.e. the company acquires licenses that give right to use the software, installed on your own servers, integrated with other systems (for example your CRM system, its e-mail system, its telephone plant) and keeps your data within its technology infrastructure. Like the On Demand model has its pros and cons cus. These depends on some key variables such as: security policy in the information that the company has.