I think people need to read this book while they are young and once again when they are older. I loved the use of animals to portray society, and it's almost like a Fable where the lessons are hidden throughout the book.
There's the kindhearted horse Boxer, who is pure-hearted but whose strength and unquestioning nature are abused by the pigs. There's the old and apathetic character in Benjamin, who has learned to just go with the flow as he's already lost hope. There's also Mollie, who is the opposite of everyone and craves the attention of humans, and as long as she is treated well, she's willing to go with them.
Of course, there are the pigs who have taken over the farm as the leaders, and even the power struggle within their own group is evident as Napoleon drives Snowball away from the farm.
Unfortunately, it seems like despite earlier warnings in works such as these, it seems like our society isn't able to heed the warnings and history keeps repeating itself over and over again.