More than you think... racists in the US and elsewhere still base their own manifestos, in part, on the likes of Mein Kampf and The Turner Diaries. Their mass appeal is no longer an issue, but they are still out there and being read by fanatics. The same (and much more) can probably be said of The Communist Manifesto. They are a minority in the western world today, but there are still Communists among us, and there are 4 Communist nations (China, Laos, Cuba, and Vietnam) and 1 unofficial one, North Korea. Elsewhere there are people in various nations who are firm believers in Communism, meaning that The Communist Manifesto and Das Kapital still affect well over 1 billion people today.