My previous post, Atom is the New JCR, sparked some interesting conversations, firstly from Lars Trieloff via private e-mail (with a option of spilling over into a pub if we ever wind up in the same town…) and now from Dan Diephouse. Both Lars and Dan made a really good point – that JCR needs to find ways to work together well.
I completely agree that JCR isn’t very worthwhile as something that will break down content silos. It does have value as an API to work with data though. Atom is quite limited in the granularity it can work with data (which coincidentally is one of the reasons Web3S exists as well). And you still need to store your data somewhere.
This pretty much matches the distinction I see – Atom is great for providing an API to your content and letting anyone use it, JCR is great for having a standardized set of facilities for actually storing and manipulating the data. In other words, Atom is the API, JCR is the method of implementation.
I think the improvements need to be made in working out how Atom maps to JCR and making that easier and it sounds like work is already being done on that from Dan's generic JCR content store for Abdera to Lars' concept of Atom support in Sling.