Chart - US Real-Time Bidding Display Ad Spending,

eMarketer estimates US advertisers will spend more than $3.36 billion on real-time bidding this year, up from just under $2 billion in 2012 and less than $1 billion in 2011. Growth rates will continue to decline as the market matures, but eMarketer expects double-digit increases in spending each year through 2017, when real-time bidding will account for more than $8.49 billion in digital ad spending—or 29% of all digital display spending.

Spending on all digital display advertising, including banner, video, rich media and sponsorships, will grow far slower—at 18.1%—as penetration and use of RTB among media buyers and publishers increases. Read the rest at eMarketer.