You can switch off a message using Off. You can switch on a message using On.
Between any two successive input lines, Mathematica prints a message with a particular name at most three times. On the last occurrence, it prints the message General.
Off[General::stop] makes Mathematica not stop repeating messages.
During the evaluation of a particular input line, names of messages associated with that input line are appended to the list $MessageList, wrapped with HoldForm. At the end of the evaluation of the n input line, the value of $MessageList is assigned to MessageList[n].
Message is printed as StringForm where mess is the value of the message mname. Entries of the form in the string mess are replaced by the corresponding .
Given a message specified as , Message first searches for messages for each of the languages in the list $Language. If it finds none of these, it then searches for the actual message . If it does not find this, it then performs the same search procedure for General::tag. If it still finds no message, it applies any value given for the global variable $NewMessage to symbol and .
If you specify a message as , then Message will search only for messages with the particular language lang.