Oracle Portal, part of Oracle's Fusion Middleware family of products, offers an integrated framework for building, deploying, and managing enterprise portals.
History and future direction
Portal was developed from the old WebDB code base. Another product, APEX was later also developed from the WebDB code. One can think APEX as a lightweight database-on-the-web version of Portal.
Oracle recently launch a new portal solution, WebCenter Suite. It is currently unclear if Oracle will migrate it's Portal customers to WebCenter or if they will support both products.
Although predefined portlets are available, companies can also develop their own portlets in PL/SQL. Starting with Portal 10.1.4, one can also deploy standard Java-based JCR (JSR-168 portlets in Oracle Portal.
Integration with WebCenter
Oracle Portal content can be published as JCR (JSR-170) data sources and used in WebCenter.