Communism is based on the notion that the working class, who collectively constitute the main producer of wealth in society, and who are perpetually exploited and marginalised by the wealthy class, should change the capitalist system by eliminating most private property and by holding practically all wealth in common.    (paraphrasing, perhaps poorly, some info from from Wikipedia)

Getting a good explanation of Communism from a Capitalist is almost as hard as getting a good explanation of Buddhism from a Christian.  I am neither a Communist nor a Capitalist so take my above synopsis with a grain of salt.  It would be nice if we could discuss the merits and drawbacks of both Communism and Capitalism without demonizing either, but I haven't seen much evidence that it can be done 

Communists don't like it when Capitalists point out that freeloaders would be rewarded as much as hard-workers. Capitalists don't like any discussion of Communism that does not demonize it.  However, since very wealthy Capitalists control both political parties in America it is very unlikely that Communism could ever get any traction here.  That said, scaring the public about socialism is about as good a method as warmongering and flag-waiving are when it comes to self-serving politicians trying to attract our votes.