This is an unsupported feature in cinema 4d : You can use Selection Tags on Primitive Objects and even Nurb Generators ! You can use it to control the distribution of clones on Parametric Objects, to animate branches, and a few more tricks, some of which are probably still completely unexplored ...
Apparently this has been hidden in c4d for a long time. In some versions it worked, in others it didn't. Appears to depend on the platform as well. Guys like Per, Darter, Joel, Jeremy, Richard, Troyan, Brian, ... and a few more clever folks were already experimenting with this a few years ago.
Last month it surfaced again on cgtalk. ( http://forums.cgsociety.org/showthread.php?f=47&t=990527 )
Jeremy remarked : "Perhaps if we can demonstrate enough interest, and some samples of why this would be useful, it might get elevated to an actual feature."
So this is me playing with it for about 15 minutes. Nothing too fancy, just testing out the basics.
The first part is some experimenting with changing Subdivisions on Primitives and cloning onto the Selection. The second part is using it on a Sweep Nurb with an Extrude Deformer to do some branching.
Here's David and Jeremy playing with this as well :
Since you're watching and reading this, you're probably a c4d user and you may want to do some experiments with this yourself ;)
If you come up with something interesting, it would be cool to upload a quick screencast or a scene file somewhere, and post a link to it in the thread on cgtalk or in the comments here.
EDIT : I did this screencast on Win7 / Darter had it work with 12.048 under OS X 10.6. / So did Troyan. / so did Joel on 10.7.
EDIT : People tend to forget to actually drag the Selection Tag ONTO the Object, not just next to it.
EDIT : Follow-Up on the second part : check http://screenr.com/2rWs for a way to use this technique to apply different textures to different Polygon Selections of Primitives with Extrude Deformed Geometry
EDIT : In some versions it worked, in others it didn't. I recorded this with R12. In R13 apparently it no longer works.