March 29, 2013 at 8:34 PM ET
Noticed a lot of profile pictures changing this week on Facebook? It was a nationwide trend, as users on the social network responded to the Human Rights Campaign's request for them to substitute a red-and-pink equal sign for their profile photos in support of same-sex marriage, with the nation's highest court hearing two cases on the issue.
Facebook knows, of course, whenever someone changes their profile picture, and there's a normal daily rhythm for American users. But Facebook's investigation showed a huge bump in picture changes just after the Human Rights Campaign began its effort.
"While millions of U.S. Facebook users update their profile photos on a given day, we found that significantly more users — roughly 2.7 million (120 percent) more, updated their profile photo on Tuesday, March 26 compared to the previous Tuesday," notes Eytan Bakshy, a researcher on the Facebook Data Science Team, in the post.
Profile pic changes skyrocketed among younger users, especially those around the age of 30; teenagers and seniors didn't get quite as much into the spirit.
There were also some highly significant geographical trends, as illustrated by the map above. The darker the color of the country, the more people changed their profile picture. The most active county in the country was Washtenaw, in Michigan, home to Ann Arbor and the University of Michigan — and the other most active counties also contained major colleges and universities.
As some commenting on the Facebook blog post have pointed out, there's no way to know whether all these profile picture updates were in support of gay marriage, since users could just as easily be changing their picture to indicate opposition to gay marriage (or just a new look). But the correlation with college towns and the deliberate and visible campaign by the Human Rights Campaign suggest that it was mostly supportive.
The rest of the data and a few more observations by the Facebook Data Science Team can be found at the blog post itself.
Devin Coldewey is a contributing writer for NBC News Digital. His personal website is coldewey.cc.