This article opens by looking at how the meaning of communism as opposed to socialism evolved in the late nineteenth century and closes with a look at how this applies to the free software movement today. The terms socialism and communism appear in England around the 1820s as terms adopted by members of the cooperative movement who were sick of hearing their politics referred to as "Owenism". Originally the two terms were undifferentiated but by the 1840s communism was used by revolutionaries to differentiate themselves from reformists such as J.S.Mill who had adopted socialism to cover an indigestible mess of reformisms.