The IBM WebSphere Application Server V7.0 Feature Pack for Communications Enabled Applications, one of the WebSphere Software Early Programs for WAS 7.0, enables you to make your WAS JEE application into a communications enabled application.
So what the heck is a communications enabled application (CSA)? Imagine your user is browsing your Web site and has a question. The user can call a customer service representative, but then the CSR has no idea what Web pages the user is looking at and can't help the user browse to find what they're looking for. With CSA, the user can click a button on the Web page to contact the CSR, which then opens up a connection like an IM chat, a VoIP discussion, or the user enters their phone number and the CSR calls it (aka click to call). Not only does this make it easy for the user and CSR to have a conversation, but the button can also enable the CSR to share the user's browser screen, looking at the same Web page the user is seeing, and together they can collaboratively browse the Web site (aka cobrowsing). This enables the CSR to help the user find what they're looking for and even fill out orders and other forms. A similar button can enable a user to share a Web page with another user so the two can then browse the same site together from two different computers (aka peer-to-peer cobrowsing). This would, for example, enable two users to jointly browse for a gift for a third person without having to be at the same computer.
There are non-WebSphere, third-party packages for CSA, but all they really enable is click to call. The CSA is not built into the app, so the CSR can call the user and know something about the user's context when they clicked the button, but can't cobrowse. The app developer also has to learn how to program the CSA package which doesn't necessarily have a well-defined Java API like the features in WAS. Because the third-party CSA is a separate app, it has to be installed and administered separately in the runtime environment and may not have WAS's QoS features for scalability and failover. WAS CSA is a better approach because it integrates the CSA features into the WAS app, supports a single integrated Java programming environment, and runs on the WAS platform your app is already using.
WebSphere CSA is also JSR 289 SIP Servlet 1.1 compliant.
The WebSphere development team that created the CSA has their own blog, appropriately titled Communications Enabled Applications. This blog is a good place to get the straight dope on how WebSphere CSA works and how to use it. It includes several YouTube videos that show how it works. For example, here's one where Erik Burckart, the chief architect for CEA, explains how cobrowsing works:
As the video shows, the two peer-to-peer cobrowsing users can chat about what they're browsing using an IM built into the Web site.