A portal is a method for integrating computer applications across boundaries set up by organization, location or differences in technology. A portal offers access to a wide range of applications already in place, using software provided by portal application vendors. Portals make it possible to retain in place local applications while delivering to users a single view how to access a wide range of results.
Portals can be seen as an overlay on top of existing applications. They leave undisturbed legacy applications. Portals are an add-on layer. They are not substitute method for creating applications.
Nevertheless, portals provide useful functions, such as Single Sign-On access control. This requires a user to authenticate themselves only once for access to multiple applications. Portals also offer connections between functions and data from a variety system sources. Some portals offer components (portlets) for navigating between related applications. This makes it possible to connect information that originates from separate sources. Portals also offer a way to personalize user access to diverse applications.
There are over thirty vendors that offer portal software. Major vendors such as IBM, Oracle and Microsoft (SharePoint) offer portals only as proprietary applications. These are costly licenses that require a considerable investment in development and testing before the portals can be implemented. Invariably, they lock–in a user to complete dependence on the vendor.
The use of portals should not be confused with Software-as-a-Service (SaaS) cloud computing.
SaaS does not depend on existing in-site applications for access. SaaS requires hardly any development expense and can be implemented rapidly. SaaS can potentially deliver almost every functions, such as offered by SharePoint. The user organization does not have to maintain diverse applications that are used by a portal where it serves primarily as an integration means. SaaS also calls for a Single-Sign On access control authorization. However, security is enforced across every application whereas in the case of portals the user still needs to assure the security of all access sources.
The business model of a portal differs from the business model of SaaS computing. Portals can be seen as integration overlay software that simplifies the user interface. However, it increases operations and maintenance costs. Portals increase system complexity and therefore complicate security.
SaaS replaces the supporting infrastructure of applications entirely. The infrastructure as well as all applications will disappear and therefore require no upgrading or maintenance. There is little doubt that SaaS will cost much less than continuing with a reliance on portals.
During the migration to SaaS it is likely that a hybrid combination of portals and SaaS would be useful. Existing portals can remain place while increasingly shifting to applications as they become available as a SaaS service.