Facebook users who are puzzled by seeing red equal signs all over their News Feeds, here’s what they’re all about: With the Supreme Court hearing arguments Tuesday on California’s Proposition 8, which mandates that the state recognize only marriages between men and women, Human Rights Campaign is urging Facebook users who support same-sex marriage to change their profile pictures to the red equal sign image.

HRC wrote in a post on its Facebook page Monday:

Who’s wearing red tomorrow? Show your support for marriage equality — make your profile image red for tomorrow and check out www.hrc.org/StandForMarriage for more ways to get involved!

Readers: Have you seen the HRC’s red equal sign on your News Feeds?