Read this article. Excommunication is serious business, and my only real comment on this is that I wonder when I'm going to have a conversation with my mother about my lapsed faith. The answer to this is obviously "never," but I feel like this goes a long way in explaining why I don't think I left the church - it left me, or anyway it doesn't want me, and I don't care to go where I'm unwanted.
Aside: dig the sidebar where the European inquisition put heretics and non-believers to death. Thank fuck for separation of church and state and abolishment of capital punishment, right? Oh.