Pink in the London Daily Mail May 26th 2006 said this song is about losing a loved one to drugs: "My life was insane, I was (in her youth) out of control and doing lots of stupid things. Some of my friends were selling crack, and I got into drugs too. I've always been honest about that, although I don't like going into details. I've got lots of young fans and I wouldn't want to give them any ideas. I found a friend dead from a drug overdose when I was 14. He was a male friend, not a boyfriend. Most of the people at the funeral were just children. It should have been a wake-up call for me, but it wasn't." According to Pink, the song is about "the grieving process. You can look at somebody, he might be right there, and the next Monday he might not be."
Pink's close friend Sekou Harris died of a heroin overdose when they were only 14. The tragedy inspired Pink’s 2006 song, “Who Knew.”
source: http://www.nydailynews.com/entertainment/gossip/singer-pink-save-best-friend-drug-addiction-article-1.1341547
Pink in the London Daily Mail May 26th 2006 said this song is about losing a loved one to drugs: "My life was insane, I was (in her youth) out of control and doing lots of stupid things. Some of my friends were selling crack, and I got into drugs too. I've always been honest about that, although I don't like going into details. I've got lots of young fans and I wouldn't want to give them any ideas. I found a friend dead from a drug overdose when I was 14. He was a male friend, not a boyfriend. Most of the people at the funeral were just children. It should have been a wake-up call for me, but it wasn't." According to Pink, the song is about "the grieving process. You can look at somebody, he might be right there, and the next Monday he might not be."