Both movements involve using, modifiying, stealing or vandalizing someone else's artwork. Sometimes litigation ensues.
I have inserted Marcel Duchamps' L.H.O.O.Q. (1919), where he puts a mustache and goatee on the Mona Lisa.
Contemporary artists continue to annoy, harass, steal, disrupt and dismay us. Decades later, their works will be valued and celebrated. My favorite is http://www.whitneybiennial.com/. The artist Miltos Manetas stole the Whitney's name and a very good domain name and used it to build a version of the Whitney's 2002 Biennial that included his web-based artworks. He told the press that he was going to surround the Biennial with U-haul trucks with screens showing web-based art that he likes. He never did, but he created a huge uproar.
The social or artistic value of a work that borrows so heavily from another's work is not always apparent. For example, the "appropriation artist" Richard Prince photographed Marlboro advertisements, took out the wording of the advertisement, and blew up the photographs without any other modifications. Pure copyright infringement? One of his photographs reached a world record for photography when it auctioned in 2005 for over $1.2 million.
The artist Jeff Koons (who recently won a case against a photographer whose image he placed in a painted collage) has similarly caused scandal, litigation, and has eventually reaped tremendous financial rewards for reinterpretations - or outright taking - of works under copyright.