In-lining extensions and hierarchy for Atom

Linked resources are a real treasure in Atom. They allow you to connect, through hypertext, all kinds of things in to a useful content model. No wonder all sorts of Atom applications have invented custom or new standard link relations for Atom.

One challenge with linked resources, though, is that one has to make separate network requests to obtain their representations. While this is exactly the approach taken in HTML, there are some benefits to making representations of linked resources available in-line with the referring Atom document such as reduced network dependency and greater responsiveness.

Introducing an in-line representation technique for such situations, while making Atom as a format more useful, does nothing for standard Atom clients such as feed readers. These standard clients could, over time, provide better access to Atom extensions. For example, some feed readers do not provide adequate support for presenting categories. Others don't make available the "replies" link. A part of working with the Atom format is the opportunity of unimaginable extensibility and the disappointment of uptake and general utility. 

In any case, we have revised the atom-hierarchy I-D and it is available in both text and HTML. There is a demand for separating the in-line parts from the hierarchy parts, and this 01 version keeps them apart inside a single I-D.