Software as a service (SaaS) is a software delivery model which is also referred to “on-demand software”. The software and its associated data is hosted centrally or in a cloud on an infrastructure that the vendor manages and is normally accessed by a client using a web Browser. SaaS has become a common business model for many business functions like accounting, enterprise resource planning, service desk management and many others.
Unlike typical services where charges are being demanded upfront providers usually price applications using a subscription fee, most commonly a monthly fee or an annual fee. Since the provider has economies of scale and scope the price should be lower than buying a software the conventional way.
Leitfaden für SaaS-Anbieter: leitfaden_saas_20090310_web_neu_1_.pdf