Mike and Bernd currently attend the DevCon Europe 2004 (German site). They are presenting two talks - one is an overview of #develop, the other an in-depth talk on the architecture of #develop. To better visualize the idea of the addin infrastructure, Mike revamped the Addin Scout.

There is now a real tree view of the addin tree, where you can see which tree node is extended by which addin:

The addin view in contrast tells you exactly what tree nodes are extended by an addin.

Pretty neat tool for explaining the concept of the addin tree.