(CNN) For decades now, millions of Americans have embraced the day-after-Thanksgiving shopping bonanza known as "Black Friday." Then came "Cyber Monday," online retailers' chance to cash in on the holiday buying frenzy.

Now consumers are being urged to open their wallets for "Giving Tuesday" (sometimes written #GivingTuesday), a day to raise funds for charitable causes.

Giving Tuesday started in 2012 by the 92nd Street Y and the United Nations Foundation

"It was also an experiment in how powerful social media could be as a force to encourage charitable giving and sharing of acts of kindness," explained Asha Curran, CEO and Co-Founder of Giving Tuesday.

"When this started out a couple years ago we were pretty skeptical about it," admitted Colleen Finn Ridenhour, Senior Vice President of Development for Habitat for Humanity

"There's been, in a short amount of time, a great deal of awareness around this campaign," Finn Ridenhour told CNN. "As the public has become more familiar over the last couple of years we've seen folks raising their hands and joining in more significantly."

"Giving Tuesday enables us to have a formal anchor on the calendar that ushers in and starts the season of giving," said Ettore Rossetti, Senior Director of Social and Digital Innovation at Save the Children

#GivingTuesday is a time to give back in #gratitude for all that we have been given. By #donating to CRS, you can change the lives of people affected by natural disasters, disease and poverty. https://t.co/lU5snNAdvl #givingback pic.twitter.com/9gBKw47S96 — Catholic Relief (@CatholicRelief) November 25, 2018

"Our annual giving is growing [as a result of the campaign] but it's also becoming globalized. It's becoming not only a national day but an international giving holiday," Rossetti said.

Last year alone, Giving Tuesday raised $400 million online in the US, according to the campaign's official website

To take part in Giving Tuesday, all you need to do is pick a charity you trust and visit their website to donate. Many organizations are including the hashtag #GivingTuesday in their recent social media posts as a reminder.

Or, you can always head to cnn.com/impact and give to any of the charities featured there.

"The beauty of #GivingTuesday is that everyone has something to give -- whether it's donating money, volunteering time or giving essential resources like food and clothing," said Curran.