I love it when bands find a new and inventive way to get their music to their fans. Radiohead pioneered it 7 years ago with "In Rainbows". I remember that release being so big that the White House Press Secretary was asked to comment on the band's pay what you want model. Think about that for a second. An alternative rock band releasing an album, made it all the way to the Press Secretary of the White House!!
Other bands such as Nine Inch Nails, Kayne West, and Beyonce saw how successful this surprise/inventive release model could be and soon followed suite, to great success.
The only drawback is this release method has only been successful with very well known bands for the most part. For an up and coming band to break through, and gain notoriety with this model isn't impossible but can rather be difficult. Mainly because they are fighting to gain notoriety, while bands like U2, Radiohead, and Kayne West have notoriety.
Nevertheless, it's still really cool to be listening to a new U2 album today, when no one expected. Plus I really like the album thus far...