Dive Brief: 

• An adjusted prediction yesterday from eMarketer reported that spending through real-time bidding channels will be $3.37 billion, or 19%, of total display ad spend in 2013. 
• The industry doesn't necessarily agree with eMarketer — vendors believe the number is higher, as evidenced by The Rubicon Project's report that 40% of online display advertising is traded through RTB. 
• Many ad buyers feel that anything over 20% is an exaggeration based on their experience. 

Dive Insight: 

Vendors, of course, have an investment in RTB, so that may skew how they look at their numbers. Regardless of the exact piece of pie RTB cuts out of overall online display advertising, the reports across the board show that RTB is on the rise.