In a recent article (April 2, 2009), eMarketer forecast that mobile advertising will rise from $648 million in 2008 to $3.3 billion in 2013—a 5-fold increase in 5 years.  This increase is expected to be facilitated by more pricing plans that include data and phones that are better able to present mobile content.  While this is a large increase, the total amount is still a small portion of overall online ad spend, which is projected by eMarketer to be $42 billion by 2013, up from $23.6 billion in 2008. (Search advertising represents the biggest portion of this—more than twice as large as the next biggest category.)  That is enough to make that 5-fold increase seem small, as mobile captures an ever-larger slice of the online ad spend pie.