The Subject lookup is very unique in Dynamics CRM due to the fact that it is the only lookup that is formatted in an hierarchical tree structure. The typical use, at least in the out of the box arena, is around incidents and knowledge base articles. Recently I was working with a customer who wanted to leverage the Subject lookup, and had a whole bunch of Subjects (both active and inactive) that needed to be imported. Here are a few things I learnt along the way which might prove useful to you!
