The release of the latest U2 album Songs of Innocence for free for all iTunes users must have seemed like a win-win plan - free music for the band's fans (and maybe many new ones), a high-profile marketing campaign for Apple and a reportedly generous payment for the band themselves and their label. 

The reaction has been far from universally positive - and not just in terms of the response to the music itself, which has divided music critics. Some complained that the album was added to users' accounts without their permission.

Irish musician Paul Brady has shared his opinion of the release deal. In a Facebook post, he writes "so U2 gave away their album? I guess any of us would give away our work in return for reputedly $100 million. But what about the rest of the musical artists in the world who were kind of hoping that proceeds from the sale of their records to the public might go some way to offsetting the cost of producing them?"

"This is a further and highly visible nail in the coffin of a sustainable music business from a band that continually waffles on about fairness and human values, " he adds. "Music costs money to make. It has value. It should not be given away free. Shame on you, U2."

Interestingly, the free album appears to have had a positive effect on sales of U2's music, with many of their earlier albums having since appeared in the top 100 album charts on iTunes. As of writing, The Joshua Tree is at number 15 in the Irish iTunes charts.