Judith Burton has written a good piece on context automation and what we're doing at Kynetx. She says:

When browsing the Internet, each web site encounter throughout the browsing episode is a separate or ad hoc experience. There is no thread or connection from one site to another except in the user's mind. The user must hold the context of the browsing episode outside of each web site encounter.

From Context Automation
Referenced Tue Feb 17 2009 09:30:53 GMT-0700 (MST)

And then later:

To create a context across multiple sites, an abstraction layer may be employed that is capable of gathering information from the user and from each site throughout the entire browsing experience. This interactive cross-site abstraction layer is called Structured Browsing.

From Context Automation
Referenced Tue Feb 17 2009 09:31:45 GMT-0700 (MST)

Having an abstraction layer that is easily programmed on one hand and easy to interact with on the other is the key. Such an abstraction layer can be programmed to manage different kinds of context while giving the user a consistent experience.

We're working hard to get the Kynetx abstraction layer, which we call KNS, ready for a more general deployment. We hope to offer limited access to developers interested in creating contexual Web experiences in the next several months. In the mean time, I'll be blogging thoughts here. Also, if you haven't read the white paper (PDF) it will explain much of this in more detail.