Flat format or hierarchical structure?

We have a client who cannot decide whether to leave his organization in a flat format or whether to have a hierarchical structure. What are the benefits of the hierarchical structure?
I strongly suggest hierarchical. You can keep it simple -- just one level, such as "Joe Jones/Acme." There are several security and administration features in Domino that do not work correctly with flat IDs.

This was first published in July 2003