Now that Halloween is behind us, it's time for Madison Avenue to focus on the mad dash to the finish line, i.e., Christmas.  The National Retail Federation is predicting that Americans will spend from $717 billion to $721 billion during this holiday shopping season, a gain of 4.3 to 4.8 percent from 2017.  That would bring glad tidings for quite a few media companies and agencies, eager for advertising dollars, fees and commissions.  But unfortunately, some Christmas stockings are turning out to be filled with lumps of coal.