Neil Postman writes:
"Now . . . this" is commonly used on radio and television
newscasts to indicate that what one has just heard or seen has no relevance
to what one is about to hear or see, or possibly to anything one is ever
likely to hear or see. The phrase is a means of acknowledging the fact
that the world as mapped by the speeded-up electronic media has no order
or meaning and is not to be taken seriously. There is no murder so brutal,
no earthquake so devastating, no political blunder so costly--for that
matter, no ball score so tantalizing or weather report so threatening--that
it cannot be erased from our minds by a newscaster saying, "Now .
. . this." The newscaster means that you have thought long enough
on the previous matter (approximately forty-five seconds), that you must
not be morbidly preoccupied with it (let us say, for ninety seconds), and
that you must now give your attention to another fragment of news or a
commercial.
(Amusing Ourselves to Death 99)