EMarketer projects that two-thirds (66.6%) of the $19.50 billion spent online this year will go to the so-called Big Four; in 2005, the four portals captured more than half (53.7%) of all online ad spending.
EMarketer attributed the dominance to traffic and the brand equity each has built. Each of the four averages 100 million or more unique visitors every month.
EMarketer aggregated its data from company reports and calculations it made in February. —Carol Krol