The Information Layer
Over the past three years, I have been making various observations about processes. I especially focused on processes that involved my work, front-end development. While studying interaction design, starting in 2009, I observed that the current view of the UI layer was not granular enough. That is, there was something happing that was not being fully depicted by the previous model.
Others have given these layers different names over the years. But the difference in my model was a separation of content and semantics. That is, having structured content (metadata/XML/JSON/etc.) without the contextual meaning attached to it (via HTML). As an example, take the library. We have a room with stacks full of books, all different size, colors, and shapes. At this point, we have "pure" content and we are in the Information Layer.
Now apply the Dewey decimal system to that stack. Even though we have information about each book, what we lacked was some sort of context to view information. That is the Semantic Layer. It’s the point where we can view information in more ways beyond the obvious, such as search relevance and related topics.
During the same time, blogs and sites like Twitter were giving their content away in the form of XML and JSON formatted data. Now, users had a way to get information and display in any manner they wanted. And now, they could use this same process on any device and adjust accordingly. In the end, that is the separation of content (Information Layer) and context (Semantic Layer).