Buy a stamp and mail a letter or a postcard on Saturday.

That’s what one Facebook event, titled “Because we love snail mail,” is asking its participants to do. As of Thursday morning, more than 400 people had signed up, while another few thousand have been invited.

Hardly enough to keep the Postal Service from hemorrhaging the $25 million it loses each day.

But there’s a delicious irony in the thought that social media might help rescue the financially ailing U.S. Postal Service when e-mail and online bill payment get blamed for the drops in mail volume and revenue. “Just” 160 billion pieces of mail were delivered in 2012, compared with 202.1 billion in 2003, according to the USPS. On the other hand, the American love affair with online shopping has driven up package delivery.

A Wheaton, Md. resident holds greeting cards ready to mail, but the mailbox across the street was recently was torn out.. (Marcus Yam-The Washington Post)

Last week, Postmaster General Patrick Donahoe announced a proposal to cut Saturday delivery, except for packages and to post office boxes. Since then, Facebook pages and thousands of Twitter posts have focused attention on the woes of the Postal Service.

On Wednesday, Donahoe testified before the Senate Homeland Security and Governmental Affairs Committee, and lawmakers drew battle lines between the needs of urban versus rural areas. “If we’re going to have mail delivery that’s going to work for urban areas, it damn well better work for rural America, too,” Sen. Jon Tester (D-Mont.) said.

Those lines reflect similar divisions between the haves and have-nots with access to broadband Internet. Cliff Guffey, president of the American Postal Workers Union, cited a Pew report that one in five American adults does not use the Internet.

Senators from Wyoming and Alaska also questioned the elimination of Saturday delivery out of concern that rural citizens would not have any other access to mail.

The legality of the decision also remains a concern.

Groups such as the National Association of Letter Carriers sent live tweets after the hours-long testimony. More than half a million people work for the Postal Service, making it the nation’s second-largest employer, behind Wal-Mart. Shrinking that work force threatens middle-class jobs that have been especially popular with veterans and with African Americans, according to Philip Rubio, author of “There’s Always Work at the Post Office.”

In the meantime, the possibility that there won’t be Saturday delivery has generated grass-roots opposition as seen on social media. People suddenly love “snail mail,” as it’s been called disparagingly in the past, when faced with the prospect of losing it one day a week.

Social media has also given a voice to those questioning the Postal Accountability and Enforcement Act of 2006; some say the burden of mandated health-care prepayments for retirees 75 years into the future — not required by any other federal agency — is causing much of the Postal Service’s financial troubles.

On the lighthearted side, The American Housewife @WhatIDoAllDay sent a series of tweets asking if she might “single-handedly save the US Postal System” by mailing letters to those who ask for them. She beseeched people that if they liked mail, they should provide “something to deliver” by writing a love letter, a thank-you note, a postcard.

“From now on instead of saying, ‘You should tweet that,’ I’ll shout: ‘Put a stamp on that! I’m sure your mother would like to hear from you,'” she tweeted. On Valentine’s Day, she tweeted that she would rather receive “a heart-shaped box of wet cigarette butts than an eCard.”

Three generations of a family in Missouri and Arkansas created a Facebook event to encourage people to return to the art of letter-writing. Donna Charton of Jefferson City, Mo., told me she that by asking people to buy stamps and send mail Feb. 16, it could be “like a flash mob” directed at the Postal Service

Her niece Heidi Charton of Little Rock, Ark., set up the Facebook page, which they plan to turn into a regular Facebook group as a forum for people who like writing letters. She was interviewed on Jim Bohannon’s radio show Wednesday about the group’s efforts.

The Chartons’ love of mail is inspired by Donna’s 88-year-old mother, Honey Charton,  who lives in a retirement home in Columbia, Mo., where residents line up to wait for each day’s mail. Honey told me she “grieves” over losing one day of mail delivery, especially since her hometown newspaper arrives on Saturdays. She has fond memories of the importance of the post office, telling me stories of her mother’s 29-year career as a rural postmistress in rural Arkansas, appointed by President Franklin Roosevelt.

“It’s history in the first person when you look back on letters,” Donna told me, mentioning Thursday’s release of the love letters between President Lyndon Johnson and his wife, Ladybird, at the LBJ Presidential Library.

Individuals have taken up the defense of the Postal System, as well. A letter carrier in Oklahoma City posted a lengthy status update on Facebook, shared from another carrier, in the hope that it would spread across social media. “I’m always dismayed when, during discussions of this sort, someone invariably says something to the effect of “my tax dollars are paying your salary”. No, they are NOT. Stamp and other product sales pay my salary.”

It’s true. So far the Postal Service does what it does without tax money. But Donahoe said that could change if reforms are not instituted that go beyond cutting Saturday delivery. Otherwise, a taxpayer bailout may be needed to save the mail.

As we wait for Congress to take action, why not write a letter this Saturday?

Diana Reese is a freelance journalist in Overland Park, Kan. Follow her on Twitter at @dianareese.