FaceUp got rid of the Echo Sign In Sheet Thread. We've done away with those for a while because it's more spam then anything because they either type their GamerTag or "Signing In" for their post in the thread.
I would ask a XC or XI gammertag to find out. It also depends on if you LEFT the Community: Meaning you decided to leave. Or if you Had To Leave: Meaning you XBox was down or you just went inactive.
If you willingly left you might as well forget about it and find a new community outside of XG