Why The Web?
While REST is a set of architectural guidelines applicable to various types of computing infrastructures, Resource Oriented Architecture (ROA) is only coupled with the web. This architecture is therefore useful mostly to businesses that consider the web as the computing/publishing platform of choice.
The power of the web seems to mostly reside in its ability to lower the barriers to entry for human users who may not be highly trained in using computing machinery. As such, the web widens the market reach for any business that decides to publish some of its content in electronic format.
On the web, such published content is regarded as a web resource.
Read more about this topic: Resource-oriented Architecture