Software as a Service
Software as a service is where computer applications are accessed over the Internet rather than being installed on a local computing device or in a local data centre. So, for example, people may use an online word processor like Google Docs, an online database application like Zoho Creator, an online photo editor like Pixlr, or an online invoicing application such as Zoho Invoice. Many SaaS applications are free to use, at least initially.
SaaS can provide its users with many benefits. These include the general cloud computing advantages of dynamic scalability and any device independence, as well as the benefit of being able to use an application without incurring fixed costs. Many SaaS applications are also collaborative. This allows multiple users to share documents and even to work on them at the same time. For example, in the Google Docs spreadsheet different users can work on different cells simultaneously. The cells different users are working on are locked-off and highlighted in different colours. A real-time chat window can also be opened up alongside the spreadsheet to further enhance collaboration. For more information on collaborative working using Google Docs, you can watch the now classic video Google Docs in Plain English.
Taking collaboration further still, the outputs of some SaaS applications can be embedded in other web pages as web service gadgets. For example, a Google Docs or Zoho Sheet chart can be mashed into another website. There it will automatically update when the data in the online spreadsheet that is generating it is changed. SaaS applications are also constantly updated, which can free users from the “upgrade hell” of a major traditional software package revision.
The disadvantage of SaaS is that it is basically a take-it-or-leave-it form of cloud computing. This means that businesses and individuals who require direct access to cloud computing hardware on which they can run their own applications cannot use SaaS. Rather, they need to cloud compute at the platform or infrastructure level using either platform as a service (PaaS) or infrastructure as a service (IaaS).