FEMINIST ICON Gloria Steinem welcomed more than a half million people to the flagship Women's March in Washington, D.C. on Saturday in what was probably the largest protest in the nation's history. "This," she said, "is the upside of the downside."

The downside, the election of a troublingly unqualified man as president, motivated about 3 million women, men and children to gather in 637 locations around the world, according to a running tally of crowd estimates collected by a Connecticut professor. The upside: a "Thanks, we needed that" moment in contrast to Friday's grim Inauguration Day, which began a new, frightening era in these United divided States. (At 50,000, attendance at Philadelphia's event was more than double what was expected.)

Looks like a movement to us - and the way it began and evolved can serve as a road map for the future.

It was grassroots and local, led by a younger generation with little to no experience in politics or even in organizing. A post suggesting a women's march appeared on the Facebook page of a retiree in Hawaii the day after the election. Soon, plans for marches in cities large and small were showing up online. It could not have happened without social media, but the achievement took so much more energy than the "slactivism" that begins and ends with signing an online petition. People who had never done anything like it before - like Emily Morse of King of Prussia, whose Facebook post kicked off the Philadelphia march - stepped forward to make the complicated arrangements for permits and insurance and emergency medical services.

It was homemade and personal. While many of the creative signs echoed each other, most were hand-lettered. The "Pussyhat Project" that began with a couple of California women gathering patterns to knit, crochet or sew the distinctive pink hats, went viral, eventually including thousands of crafters giving away handmade hats to friends and strangers, providing their names and contact info in the hope of creating relationships.

It established a community. One couldn't be in the midst of those throng of like-minded people in high spirits on Saturday and feel isolated or helpless.

Most important, it didn't end on Saturday. March organizers have collected names and, going forward, will provide specific ways to harness this new energy into civic action that goes beyond political campaigns. To get involved, search the Internet for a group near you.

Meanwhile, the new administration spent its first two days spouting provable falsehoods about the size of the crowds on Inauguration Day, confirming that its motto will be "Who do you believe, me or your own eyes?" It doesn't matter; we have work to do.