premise: Kerplunk was released through online sale only.
hypothesis: BlueMelon is a premium photo sharing web service , providing for storage and online sale of images . Kerplunk is the second studio album by American punk rock band Green Day , released on December 17 , 1991 by Lookout ! The album officially includes only 12 tracks , but the versions released on CD and cassette also include the 4 tracks from the Sweet Children EP . As of November 2013 , Kerplunk '' has sold more than 1,000,000 copies in the United States and more than 4,000,000 copies worldwide .