Portals
Webopedia, a web encyclopedia, defines portals as: 'Commonly referred to as simply a portal, a Web site or service that offers a broad array of resources and services, such as email, forums, search engines, and on-line shopping malls. The first Web portals were on-line services, such as AOL, that provided access to the Web, but by now most of the traditional search engines have transformed themselves into Web portals to attract and keep a larger audience.'

More portals
As interesting an true as it is, it seems incomplete as it only defines general portals, not mentioning enterprise, collaboration, vertical, and specialized portals of all kinds. While all portals tend to offer a broad range of resources and services, more and more offer specialized services to (often) specialized users. This is certainly the case for enterprise, vertical, industry, collaboration, virtual profile, and resource sharing and management portals.

Collaboration portals
Portals offer powerful concepts or patterns for efficient collaboration. They are an effective tool to bring together, share, save, and optimize resources and resource usage. Portals, especially specialized portals, including enterprise and collaborative portals are key to the new network society, industry, and economy.

Purpose
Portals are distributed network tools that provide secure collaboration environments for their users to securely pool and share together their respective, secure, and confidential assets and resources. Portal users sharing resources can also be competitors in various activities. Security and confidentiality are prime issues (seeSecurity.

Integration
New portal and portlet standards like JSR-168 define a basic portal management infrastructure but effective portals need to integrate other important components like work flow management, validation infrastructure, and rich GUI development support.

Costs of failure
Portals provide an indispensable integration and collaboration platform for distributed applications. They are key to successful distributed application environments and portal failure and inadequacies leads directly to project failure, cost and investment waste, and major frustrations for all parties.