The NPD Group’s annual tracking of US video game sales revenues noted a significant increase in the category that includes mobile games and digital add-on content (that is, in-app virtual goods and full-game downloads). In 2012, the “other” category grew to $7.7 billion, up from $5.4 billion in 2009. By contrast, console revenues shrank from $10.1 billion to $6.7 billion during the same period. It should be noted that “other” includes all digital content, but the study did not indicate what percentage of this category came from mobile in-app virtual goods. Read the rest at eMarketer.