Conversation so far:
Did the group Van der Graaf Generator influence many people?
Van der Graaf Generator have inspired several notable musicians, including Rush, John Lydon, Marc Almond, Graham Coxon, Luca Prodan, Mark E. Smith, John Frusciante, Bruce Dickinson and Julian Cope.
When was the group Van der Graaf Generator popular?
Van der Graaf Generator have generally been commercially unsuccessful outside of early 1970s Italy.

Question: What type of music did they perform?
Self-contained rewrite: What type of music did the band Van der Graaf Generator perform?