Twitter is a feed of what's getting attention right now, a cresting wave of what people are talking about. If you have to make an analogy with food, it's like

Twitter is a feed of what's getting attention right now, a cresting wave of what people are talking about. If you have to make an analogy with food, it's like ice cream from a street vendor on a hot day. It's not food, its value expires rapidly if you don't consume it when it's fresh, and it's a little bit addictive.