If you spent much time on Facebook last week you most likely saw a lot of pink and red as people around the country changed their profile photos in support for marriage equality.

It started with the Human Rights Campaign (HRC) in an effort to encourage supporters relative to the US Supreme Court meeting last week to begin the debate on the future of same-sex marriage in the US.

On Monday March 25th at about 1pm EST, the day before the Supreme Court’s deliberation of California’s same-sex marriage ban, the HRC posted a Facebook status urging followers to change their Facebook profiles to its official “equal sign” logo in pink and red color scheme as a show of support.

The ‘red equal sign’ photo quickly spread across the social networking sites, reaching more than 9 million people and 77,000 shares directly from HRC’s Facebook page. Then, several celebrities and public figures picked up on the trend by switching their profile photos from actor George Takei and singer Lance Bass to Beyonce to Maryland governor Martin O’Malley and at least 13 United States Congress members.

By the morning of March 26th, the Facebook profile trend had been picked up by dozens of media outlets including TIME Magazine, ABC, CNN, Mashable, MSNBC, Forbes and more.

More celebrities and brands/companies jumped on board with derivations of the symbol.

Martha Stewart

Absolut Vodka

Bud Light

Lots and lots of creative versions were posted.

By Friday March 29, it was reported that nearly 3 million people had changed their profile photo on Facebook alone. It was so popular that researchers at Facebook crunched the numbers to figure out exactly how many people changed their profile photos for the event and more about them.

From that analysis you can see the bump in profile updates below. “Using a time series model, we can decompose the trend we’d like to examine from the seasonality in the data. We find that the increase in uploads does indeed start around the time when HRC began urging their Facebook followers to change their profile photos at 1 p.m. EST (dashed line).”

Who changed their profile photos?

Thirty-somethings showed the greatest increase in updating their profile photo (see below). “This suggests that on average, roughly 3.5% of 30-year-old Facebook users updated their profiles in response to the events surrounding the HRC campaign. We also found a small, but significant difference expression between genders. On average, 2.3% more self-reported female users updated their profile photo, compared to 2.1% more self-reported males.”

Where were the heaviest concentration of those that changed their profile photo?

The geographic divides are fairly apparent in this map: same-sex marriage gets more support in the Northeast and West, less in the South. The data also showed that, unsurprisingly, those living in college towns were the most likely to change their profile pictures.

A Washington Post-ABC News poll showed that “58 percent of Americans now believe it should be legal for gay and lesbian couples to get married; 36 percent say it should be illegal. Public attitudes toward gay marriage are a mirror image of what they were a decade ago: in 2003, 37 percent favored gay nuptials, and 55 percent opposed them.” The following chart illustrates results by political party.

This PBS story does a good job of telling the story of how Facebook went pink and red.

Watch Why Facebook Went Red and Pink Over Same-Sex Marriage on PBS. See more from PBS NewsHour.

Will all this silent support matter? Maybe, maybe not. Whether it impacts the decision of SCOTUS is yet to be seen (if you haven’t read the SCOTUS blog, it’s worth a look), but I certainly thought this article from Scientific American about the power of “norms” was pretty interesting.