Excellent article by the AngloAustria blog.

Karl Marx was a spectacularly successful plagiarist, whose ideas have been responsible for the deaths of millions, but one thing he plagiarised well, stealing it from earlier French classical liberals, such as Adolphe Blanqui and Jean-Baptiste Say, was the class system.

Ironically, Marx was destitute for much of his life yet chased a life of affluence and status.