Software as a service
Software as a Service (SaaS, typically pronounced 'sass') is a model of software deployment where an application is hosted as a service provided to customers across the Internet. By eliminating the need to install and run the application on the customer's own computer, SaaS alleviates the customer's burden of software maintenance, ongoing operation, and support. Conversely, customers relinquish control over software versions or changing requirements; moreover, costs to use the service become a continuous expense, rather than a single expense at time of purchase. Using SaaS also can conceivably reduce that up-front expense of software purchases, through less costly, on-demand pricing. SaaS lets software vendors control and limit use, prohibits copies and distribution, and control all derivative versions of their software. This centralized control often allows the vendor to establish an ongoing revenue stream. The SaaS software vendor may host the application on its own web server, or this function may be handled by a third-party application service provider (ASP). This way, end users may reduce their investment on server hardware too.
As a term, SaaS is generally associated with business software and is typically thought of as a low-cost way for businesses to obtain the same benefits of commercially licensed, internally operated software without the associated complexity and high initial cost. Many types of software are well suited to the SaaS model, where customers may have little interest or capability in software deployment, but do have substantial computing needs. Application areas such as Customer relationship management (CRM), video conferencing, human resources, IT service management, accounting, IT security, web analytics, web content management and e-mail are some of the initial markets showing SaaS success. The distinction between SaaS and earlier applications delivered over the Internet is that SaaS solutions were developed specifically to leverage web technologies such as the browser, thereby making them web-native. The data design and architecture of SaaS applications are specifically built with a 'multi-tenant' backend, thus enabling multiple customers or users to access a shared data model. This further differentiates SaaS from client/server or 'ASP' (Application Service Provider) solutions in that SaaS providers are leveraging enormous economies of scale in the deployment, management, support and through the Software Development Lifecycle.
