These days, when it comes to marketing, every day is Mother’s Day.

Twenty-five years ago, when I launched an agency dedicated exclusively to bringing brands together with moms, that wasn’t the case. Back then, moms were an “undiscovered” demographic, not perceived as a distinct and worthwhile target for marketers’ time and money—except perhaps when it came to laundry detergent.

Even toys were pitched directly to kids. Cars, vacations, insurance—surely, it was the man of the house who made those decisions! Moms’ purchasing power—and their real role as CFO of the household—was neither acknowledged nor pursued in any meaningful way.

Recent years have marked a sea change, one more akin in strength to a hurricane than a gentle wind: With social media as their primary megaphone, moms have made their voices known, and companies have responded in a big way.

Last year, for example, Procter & Gamble spent millions on a program focused on the moms of Olympians—the largest advertising campaign ever in the company’s 175-year history. Today, there are 38 million US mothers with children under the age of 18 at home, and they mean business—to everyone from office supply manufacturers to music producers.

Once, the only way for publicists to reach mothers was through well-established parenting magazines. These publications were the child rearing (and juvenile-product shopping) bibles of the time. Like so many other media, many have since reduced frequency or shut down completely, while others now live exclusively on the Web.

Independent content providers such as iVillage and Café Mom soon began to capture moms’ attention and loyalty online, by providing not just a way for them to receive information from experts but to exchange advice with each other. For moms, online communities have replaced the local playground as the gathering place of choice.

The most momentous development in communicating with moms, of course, was the coming of social media—starting with the “mommy blogger.” Ten or so years ago, moms created blogs to express themselves or connect with other moms. They were excited about the occasional free product that arrived on their doorstep and eager to share their opinion of it with the world. While many bloggers still welcome the now steady stream of samples, the most influential moms see themselves as professionals who should be paid for voicing their opinions about a brand. “Sponsorships” and “ambassadorships” abound within this media category.

Women of all stages of life, meanwhile, dominate Facebook, Twitter and Pinterest. According to a recent USA Today Touchpoints analysis, 44 percent of moms visit social media sites on an average week. Almost all of the moms we work with will post on one or more of these social networks, as well as on their blogs. With moms, the need for companies to have an engaging social media presence is a given.

Meanwhile, moms have gone mobile—organizing their lives and their families by smartphone or portable tablet. They use their devices for a multitude of purposes, from keeping their kids entertained to organizing the whole family’s activities to shopping. And they love apps, especially apps for their children. In a 2011 study by BabyCenter, 52 percent of moms said they had 10 or more apps on their phone and one-quarter of them were for their kids. Clearly, brands have to pay attention to their mobile presence.

Moms have changed in other ways as well. They are less likely to be married -- about 40 percent of all children are now born to single mothers. And 37.6 percent of working wives earned more than their husbands last year, a jump of 30.7 percent from a decade ago. Moms manage their families’ lives – and bring that expertise to managing businesses. They still change diapers—but as supporters of causes or as Secretary of State, they sometimes change the world.

The lessons learned: Moms are always on the move, whether that means trading in one form of communication for another, making major purchases via their mobile device or deciding the fate of countries. They expect—demand!—that brands recognize and respond to them. They know they have power to make important buying decisions, influence other moms and impact what brands do and how they do it—and, having tasted that power, are not going to give it up.

Stephanie Azzarone is founder and president of Child’s Play Communications, which celebrates 25 years of marketing to moms this year.