My apologies for the late reply, somehow the repsonses came into 'promotions'-tab of gmail so I didn't know there were so many good answers. I was indeed looking for a description of the data that was being sent but I know understand that although the network itself is open, the data that is being sent over the network is private by default.
@pz1, @Batilan: I know I'm an absolute newbie to this community but isn't it possible to just start a wiki-page and make some requests at meetings/talks to share the node and the description of data. When a couple of nodes are published, we could somehow distill some best practices and make that into a standard. This sounds feasible to me.
Disclaimer: I just really like data 