This will prevent Michael from sending you messages, friend request or from viewing your profile. They will not be notified. Comments on discussion boards from them will be hidden by default.
“Do not fear your enemies. The worst they can do is kill you. Do not fear friends. At worst, they may betray you. Fear those who do not care; they neither kill nor betray, but betrayal and murder exist because of their silent consent.”
―
Bruno Jasienski