Qwerty- I never heard of it growing up and found out that there was such a thing when non Lubavitcher asked me about it. Of course I told them what I thought it meant- that The Rebbe is alive and well in the sense that he is treated as Rebbe and listened to even now.
But I was wondering if there was more to it, so I asked my very knowledgeable and normal Moshiach teacher in high school about it. Ended up quite fascinating