You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Copyright_infringement

Context:
Professor Aram Sinnreich, in his book The Piracy Crusade, states that the connection between declining music sails and the creation of peer to peer file sharing sites such as Napster is tenuous, based on correlation rather than causation. He argues that the industry at the time was undergoing artificial expansion, what he describes as a "'perfect bubble'—a confluence of economic, political, and technological forces that drove the aggregate value of music sales to unprecedented heights at the end of the twentieth century".

Question:
What did Sinnreich call the link between lower music sales and peer-to-peer sharing site?

tenuous