Of all the personality types I'd consider myself to be fairly familiar with, INFJs seem to me to be the most diverse and have the least in common with each other. Learning someone is an INFJ is often very surprising for me, because they are almost nothing like the other INFJs I know. It's only in their style of communication and what I perceive to be their common flaws that I sometimes notice patterns and similarities.
So, INFJs: from your dealings with other INFJs, would you say you have a lot in common with each other? Do you perhaps communicate with and identify each other through some secret INFJ code that is specifically designed to be unfathomable to INTPs, but really obvious to you?