I think the challenging part of this project will be building intuitive and collaborative interfaces on top of the bare-bones data model. The challenge comes with two parts: (1) allowing blocks to compose, so I can nest a "task block" inside a "paragraph block", and (2) figuring out the collaboration model so multiple users can manipulate blocks at the same time, eg by typing characters. Both of these aspects are un(der)specified in the Block Protocol spec.
For an example of a challenge building composable blocks, consider the suggested architecture - the project imagines different block types implemented as sandboxed iframes, orchestrated by some editor that stitches them together into a document or dashboard. This would make certain interactions difficult/impossible to implement in the browser. For example, you can't start a text selection in one iframe, and end the text selection in the next iframe. This means that each layer will need to implement many of the standard blocks, just to provide tools that operate on the contents of more than one block at a time.
I'm left wondering if there will ever be "block protocol native" apps, or if this will be more of an interoperability/import/export format between otherwise monolithic platforms that have their own much richer internal data format.
This is kind of orthogonal to what you guys are discussing, but I want a blog where new posts (and essays) can be drawn from a library of structured templates. Starting with the basic types in DITA, and then taking it forward. Extending tasks to recipes, for example. And an outline for product reviews. And outlines for (e.g.) software use cases and software requirements specs. And with templates having available all the microformats that the cool kids use.
