Cloud applications are the greatest attraction of cloud computing phenomenon. A Cloud application exists partially or fully within the cloud. It uses cloud resources to implement core features within that applications. For instance a cloud e-mail application uses cloud storage to store user data. The architecture of cloud application may differ drastically from traditional application models. For this and other reasons, designing and implementing a cloud application requires a fundamental shift in application-design thought and approach process.
Cloud applications work directly from the Internet and as a consequence can often eliminate the need to install and run applications locally ( Gmail works like this). This reduces expenditure required for software maintenance , deployment, management and support. Such cloud applications are called Software as a Service ( SaaS) applications.
