Like the album title itself says, long live life. That is basically what the album is about for me. For me the album contrasts life and death throughout, but life ultimately wins. The last song that seems more about death says "I don't want to follow death and all of his friends" referring to revenge as a friend of death. The most popular song on the album is full of life, as are other favorites.
In a world of musical artists who do shocking things for attention, Coldplay continues to be successful without trying to draw people's gaze. Unfortunately for this reason they are not very popular with kids and some teens, but mature listeners find them outstanding.