The image, replacing profile pictures on Facebook, Twitter, Instagram, Tumblr, Pinterest and elsewhere, is a makeover of the advocacy group's logo, usually a blue background with bright yellow lines. The HRC made it available in red — for the color of love — on Monday and estimated tens of millions of shares by Wednesday.
"It shows the enthusiasm and the passion," said Fred Sainz, a spokesman for the nonprofit in Washington, D.C.
Like viral campaigns of yore, supporting breast cancer awareness (pink), President Barack Obama (change your middle name to Hussein) and even Arab Spring (green), a bit of fatigue set in on some social media streams by those questioning whether such efforts serve to change any minds or, put simply, are plain annoying.
"My Facebook feed is a cascading aesthetic nightmare. Thanks, equality," Washington Post writer Dan Zak wryly grumbled on Twitter.
A photo of Justice Anthony Kennedy made the rounds with the quip: "Before we make a ruling, did enough people change their Facebook profile picture?!"
None of that mattered to the masses of same-sex marriage supporters. Some swapped matzoh for the pink lines as Passover got under way, or added frowny Internet star Grumpy Cat, who explained marriage equality would make her happy.
Bert and Ernie showed up against the red background. (They're best friends with no plans to marry, according to Sesame Street.) Another version featured Paula Deen atop the red square and lines turned a shade of yellow akin to her favorite fatty ingredient and the tagline: "It's like two sticks of butter y'all."
Takei, a noted punster with nearly 4 million followers in Facebook, turned the equal sign into the division sign for those opposed to marriage equality.
Beyonce, with more than 44 million followers there, played it straight, leaving the logo alone and adding a personal message: "It's about TIME!!! (hash)EQUALITY (hash)MarryWhoYouLove.
Fergie let the image speak for itself on Twitter, adding: "No words necessary." Montana Sen. John Tester, a Democrat who endorsed same-sex marriage on Tuesday, put the logo up as his profile on Facebook while the clothing site Bonobos swapped its usual Facebook pic for the red square using fancy white pants for the equal sign.
Martha Stewart's Facebook page used a slice of red cake with white icing to make the image and the HBO page for "True Blood" added fangs.
All in good fun?
"There's a lot of serious conversation going on and there's an awful lot of important concepts that the Supreme Court justices are discussing," Sainz said. "What this logo going viral means is individuals have reduced it to a very straightforward concept."
Steve Jones, a professor of online culture and communications at the University of Illinois at Chicago, wondered whether all the mash-ups muddle the message.
"Once you throw it together with something like Grumpy Cat it's fun," he said. "But was this message intended to be fun?"