The depth of a node in a thread is a property of the node, not of its title. Just like with usenet and email, I think that root nodes should be non-Re titled, and so should articles that change the title. The rest should get "Re:", and nothing more.

Abigail (this is my 4000th posting - more worthy as a profound meditation, but I've no interesting subjects to write about at the moment. Perhaps when I reach posting 5000).