At a very basic level, we're running into issues of terminology that are still amorphous, since the community of users and developers interested in Wave is likewise nascent and developing. This is an issue of representation, really.
For example, Paul and Ian (one of our tremendous student researchers) have been working on a robot participant that collects data about collaborative work in a given wave. But one of Wave's affordances is the ability for multiple participants to edit a single blip, or to create a series of nested replies within a higher, "top level" blip. This makes data collection a little more difficult.
These kinds of contributions are harder to collect, creating challenges for the software architecture of the robot participant and it's data representations. But they also create challenges for terminology; what do we call these kinds of user contributions?
Yesterday, Paul started a new blip within one of our existing waves for this project:
Paul goes on to offer two likely solutions to the problem of "blip depth"—one of which involves creating a tree structure of the entire wave and storing that information in AppEngine.
But as Paul and Ian continue to delight me with ingenious solutions to development challenges, I'm even more interested in Paul's brilliant term for representing the kinds of data we expect and dearly need to surface and trace. "Blip depth" says it all...