"Last year advertisers spent $9.4 billion on SEM, up 63 percent over the $5.75 billion spent on search in 2005, and beating last year's estimate of $7.2 billion. Spending is projected to grow to $18.6 billion by 2011 in North America." - SEMPO, State of Search Engine Marketing report 2006. Search marketing is the largest and fastest growing online marketing channel!
It’s a Google World United States | July 2008 Source: Net Applications, July 2008