IG stands for Instagram, it also stands for Insta-greed: US Senator

Facebook was questioned about Instagram's impact on teen mental health by US lawmakers at a Senate subcommittee hearing. "IG stands for Instagram, but it also stands for Insta-greed," Senator Edward Markey said. "Instagram is that first childhood cigarette meant to get teens hooked early, exploiting the peer pressure of popularity and ultimately endangering their health," Markey added.