Your name is added to a list of those who have resigned and according to official Dogma you no longer have access to the best of the afterlife if you resign. While they do continue to keep a list of those who have resigned, they are not "members", they are in fact listed as "resigned" and are actively contacted in the hope they can return them to the "fold"...
This would net you contact, especially so if you officially resign, but you are not "officially" considered a member. You are considered to be resigned from your membership and it says so next to your name...
I have provided you links to many sites that show you how to officially resign, because it is (uniquely in my experience) actually allowed though you will find resistance when you try... they'll try to keep you, but if you do it correctly there is official means to resign even so.
The reality is, Mormonism is actually one of the few religions that have an official means to leave the church, the originating post is simply incorrect. The problem that I have, and what I see as a form of intolerance, when shown to be in error people here seem to seize upon anything to keep the fiction alive. Very few people remain purposefully ignorant when faced with factual information provided to them, those that do are deliberately ignorant and spread what they know to be misinformation. This is a form of intolerance, and indeed is bigotry.
And according to the ex-Mormon sites... You can even get your name removed.
http://www.mormonresignation.com/