Animal Farm concerns one of the central political experiences of our time: revolution.
On those relatively rare occasions when men and women have decided to change radically the system of government they were born under, there has been revolution. It has been on the rise in the last three hundred years of human history. If we want to understand the world we live in, we must try to understand the phenomenon of revolution--the how, the why, the what-happens-then. One way of doing so is to see how an imaginative writer deals with it. You can think of this as an important benefit of reading Animal Farm.
Animal Farm is also about another crucial political phenomenon of our time, one which is perhaps unique to the 20th century: the rise of the totalitarian state. Even though he's less concerned with totalitarianism in Animal Farm than in his novel 1984, Orwell does give us an imaginative analysis of totalitarian dictatorship in Animal Farm. So another thing we can get from this book is a feel for how a modern dictatorship works.