The Commie Manifesto was not the end all, be all of Marxism, it is only the first major work of the Marxist diatribe. Das Kapital, I would argue, had more of an impact on society than the Manifesto. ie, the term Capitalism iteself.
hmmm, I'd have to disagree. Das Kapital is the kind of turgid prose that nobody really reads unless they've already drunk the kool aid. The Manifesto was an attempt to hijack the 1848 revolutions in Europe for the cause - and it succeeded in getting socialism/communism on the map.
Marx is clap-trap that certain people feel a need to believe as a way of putting bones on the emotional reaction to capitalisms inevitable inequalities. It doesnt matter what he wrote in his 3000 page book, as the stuff in there is not the animating force in the communist agenda. Hatred of capitalists (ie envy) is.