nullifies its influence
The fact that the recipient knows a form letter as such, largely
nullifies its influence. A business man who sends out a large number
of form letters a year claims that when he gets a reply beginning,
'In response to your form letter,' he knows that the effect of that
letter is absolutely lost on a large percentage of this list who
seldom or never bother to read such communications. And one of the
distinguishing marks of such a letter is the poor quality of its
paper.