Reading stories online or in the newspaper (a quaint habit of some older people) or watching them on television, we're made aware not only of the stories, but also of the fact that others deem them interesting enough to feature prominently.
If the story arouses some buzz, (or even if it doesn't), some stories will be repeated and repeated and repeated as trivial new details are discovered.
Not surprisingly, just as some celebrities are famous simply for being famous, some stories will become well-known for being well-known.
Because they know that others are, people will talk about them and even if the talk is derisive, the stories will persist.
How else to explain, for example, cable networks' incessant focus on missing and murdered young women, usually blondes?
And after a sufficient number of people know of a story, its momentum will carry it through news cycle after news cycle, whatever its importance or lack thereof.
The Danish cartoon controversy in the Middle East, for example, would not have attracted the disproportionate attention it did without people knowing that other people had rated this particular "song" highly.
That's the way power laws in social physics seem to operate.
An unfortunate consequence is that more important stories -- literally of peace and war and of justice and injustice -- are often unheralded and relatively invisible.
Another is that once a story has gained popular currency, it becomes very difficult to change one's mind about it.
Wait, we interrupt our story on warrantless wiretaps with a bulletin: A startling new clue has been found linking the brother-in-law of the woman who disappeared last month near the town of Xanadu to the woman's former personal trainer.
Professor of mathematics at Temple University, John Allen Paulos is the author of best-selling books including "Innumeracy" and "A Mathematician Plays the Stock Market." His "Who's Counting?" column on ABCNews.com appears the first weekend of every month.