Symbolism, Imagery, Allegory
One major sign that all isn't right in the world of the feed: everyone's getting horrible weeping sores. The book doesn't tell us why this is happening, but the feed chatter does clue us in a little. For example, we find out that there's so much background radiation that people have to have their children via genetic engineering; they can't have them naturally. We also see industrial accidents causing black toxic sludge that drowns whole villages. Based on this information, we can guess that the lesions symbolize the corruption of the environment—and that they're a sign the human race may not be long for this world.
Weird thing is, these lesions actually become hot fashion accessories by the end of the book, with Quendy getting so many that you can see her insides and muscles and tendons and stuff. (Not a good look.) More importantly, we get the idea that people just don't care anymore. They're going to ride the wave of destruction until the very end.