Trying to put a million people together has a way of amplifying their voices. The Million Man March demonstrated this in 1995, and gave rise to the Million Gay March, the Million Mom March, the Million Youth March, the Million Moderate March - each with its own agenda.

Now comes 1 Million for Work Flexibility - conducted online, appropriately enough, for those who prefer to telecommute to this virtual event.

The timing of the online campaign is perfect, says Kenneth Matos, an industrial and organizational psychologist with the Families and Work Institute, a Manhattan think tank.

"We're at the end of the fad stage," Matos says of the initial era, when flexible work schedules produced success stories for a smattering of companies and employees. And some want flexible work to become law. "That's a conversation we're going to have over the next couple of years," Matos predicted.

The pressure is building because that previously unpaid force of caregivers - women - is now more and more in paid jobs and unavailable for child care or elder care. The United States has neglected to put in place a national child care program, although some states are offering universal prekindergarten. But the other care crunch, an aging U.S. population, will be a growing dilemma.

Sara Sutton Fell, a Boulder, Colo., entrepreneur, launched 1 Million for Work Flexibility last week at WorkFlexibility.org. The site asks visitors to leave an email address and expect updates. Since 2005, Fell has run a national service, FlexJobs. She has a team of 36 people working around the country - mostly from their homes.

"I wanted to inspire people and give them a way to show their support for work flexibility, to contribute to the greater voice," Fell said in an interview. "So much of what happens depends on individual corporations, and it's moving very slowly."

In England, parents with young children and those caring for sick relatives have a legal right to request flexible work schedules, without being fired or punished for asking. That can include matching work hours to coordinate with children's school schedules, job-sharing, going part time or concentrating work into certain times of the year or days of the week. Employers don't have to grant the request, but they must provide a reason for denying it.

England is now debating whether to extend this right to people caring for someone with dementia. Jeremy Hunt, the country's health services secretary, calls the increase in dementia care "a time bomb," predicting that the number of caregivers will grow by a quarter to 850,000 by 2020.

In this country, San Francisco's board of supervisors has passed the Family Friendly Workplace Ordinance. Beginning Jan. 1, workers who have caregiving responsibilities will have the right to request changes to their working conditions to meet those obligations. Sen. Ted Kennedy (D-Mass.) and then Rep. Carolyn Maloney (D-Manhattan) sponsored national versions that failed.

Nationwide - or even corporate - policies are needed, Matos says, because many employees are reluctant to request time off for family obligations. It can be seen as the equivalent of saying one is not committed to the organization.

More employers will move toward offering flexible work to retain people, Matos believes, but that won't persuade every employer. "For generations," he says, "the marker of your commitment was that you were there at work."

Perhaps the 1 Million for Work Flexibility will change that. Surely, the need for families to care for loved ones isn't going away.