Currently autosubscribe to new threads/posts is off.

That means that if I create a new thread or reply to an existing thread, I don't get an email notifying me. So I have to either remember to subscribe at the time or go back into the UserCP and set the setting correctly, which is what I did.

I would suggest that you make the default setting to autosubscribe users to threads. Based on the advertising on the site, I assume that you want more traffic, if a user forgets about the board, or just gets busy for a week, a friendly email saying that there is a new post is a nice little nudge.