Animal Farm is written as an allegorical political satire about the rise of communism. Today, we don't have Stalin or Trotsky to equate to the pigs Snowball and Napoleon. Communism is not the threat to the free society or capitalism as it once was. The insult "capitalist pig" really doesn't hold very much meaning now to us as it once did. At the time this book was published, there was much fear and consternation regarding communism, Russia, and the Stalinist regime.
Animal Farm must be read in the context of the 1950s views of Socialism, Communism and Capitalism. The capitalist system is viewed as good while the communist system is viewed as corrupt and a threat to free society. We see in Animal Farm that the animals enjoyed a time of liberty and freedom, but after a while, the pigs began to revise the rules and rewrite history in favor of themselves. It took no time at all before the same oppressive system of rule overtook the farm with different leaders at the top.
I think that Animal Farm still holds meaning today as economic and political systems undergo changes.