Reuters - September 6, 2007, By Sinead Carew

NEW YORK (Reuters) - While Malcolm Gladwell's "Tipping Point" explores how a trend emerges from obscurity to the mainstream, a new book says even small trends can have big effects.

College-educated nannies, home-schooled children, spouses who are together only at weekends and home-buyers with bad credit all have the potential to change society, according to "Microtrends: The Small Forces Behind Tomorrow's Big Changes" (Twelve, $29.99).

"By the time a trend hits 1 percent, it is ready to spawn a hit movie, best-selling book, or new political movement," says author Mark Penn, who is credited with identifying soccer moms as a key to Bill Clinton's re-election campaign and who is now an adviser to Hillary Clinton's presidential campaign.

Multiple small trend groups are harder for marketers or politicians to target, but offer opportunities for those who identify new or often-ignored groups, Penn writes wth co-author Kinney Zalesne.

Among groups he identifies in the 2008 presidential election are the 12 million illegal immigrants, who cannot vote in the United States but who may influence the outcome anyway.

Anti-immigration moves, which already provoked a mass demonstration, could mobilize naturalized citizens to vote in sympathy of illegal relatives, the authors note.

"For the first time in American history, noncitizens' needs and passions might actually be the critical element that tips a presidential election," they write.

Other small groups that may bring big changes include the 5 million Americans still working after they turn 65 years old. Aside from the effect on jobs, this trend may also hurt golf club sales but boost sales of reading glasses, special phones or computers.

Then there are cougars, the 3 million older women already dating men six years younger than them. They may shrink the dating pool for younger women but do the opposite for young men, while also creating new service opportunities.

The book asks if rising numbers of well-educated nannies, often on the way to becoming teachers, will drive traditional nannies out of the market or be their champions, for example by writing about mistreatment or forming nanny unions.

It also notes that between 1999 and 2003 the number of U.S. children being taught at home rose 30 percent to 1.1 million, or 2.2 percent of school-age children. As a result, 83 percent of colleges had formal evaluation policies for home-schooled children in 2005 up from 52 percent in 2000.

Penn, the Chief Executive of public relations firm Burson-Marsteller, also foresaw difficulties in the subprime loan market, which began to show clearly between writing and publication of the book.

The book's last example is about how many of the world's roughly billion Muslims are members of extremist groups. About 0.004 percent are now in such groups but if this rose to 1 percent, it would be the world's biggest army.

But on the flip side, an earlier chapter says there are enough moderate U.S. Muslims to be a force for peace, depending on their views on U.S. policies.