Yup, everything I've ever heard through the grapevine is that congressmen will notice if they suddenly receive a big volume of calls about something.
Then again, you could say that the congressman shouldn't need a computer to understand the people he represents.
However we capped it at 435, so each congressman represents far more people than he is supposed to. I say technology has reached the point where we should remove the cap have thousands of representatives.
We should have three times as many members of Congress to get back to the representation levels of 1900.