From the article:
The Web Services for Remote Portlets (WSRP) protocol was designed to support the federation of portals hosted by arbitrary portal servers and server clusters. Developers use WSRP to aggregate content and the user interface (UI) from various portlets hosted by other remote portals. By itself, though, WSRP does not address the challenge of implementing scalable, reliable, and high-performance federated portals that create, access, and manage the lifecycle of data shared by distributed portlets. Fortunately, BEA WebLogic Portal provides an extension to the WSRP specification that—when coupled with Tangosol Coherence—allows WSRP Consumers and Producers to create, view, modify, and control concurrent access to shared, scoped data in a scalable, reliable, and highly performant manner.The cited WSRP extensions are being standardized, likely making this approach universal with the next version of the WSRP specification.