• by Tyler Loechner  @mp_tyler, September 26, 2013

European advertisers increased ad spend on online display real-time bidding (RTB) by 92% over the summer, according to Adform's latest report, "RTB Trend Report Europe Q2 2013."

Similarly, mobile RTB spend grew 67% in the Q2.

While those numbers look impressive, they need to be put in perspective. The 67% increase in mobile RTB really means that European advertisers put 5% of their budget toward it in Q2, up from 3% in Q1. Adform predicts mobile and tablet RTB campaign use to continue increasing.

Online publishers saw their CPMs increase by 30% in Q2. Adform wrote in their Executive Summary of the report that "the rise in CPMs is particularly welcome news to the industry," as "demand for RTB impressions [are] outpacing availability." With CPMs on the rise, more publishers figure to get involved.

Part of that involvement figures to be via private marketplaces. Adform wrote in the report that private marketplaces are "proving to be an attractive option for premium marketers and publishers," predicting that "in the quarters and years ahead, marketers will allocate greater portions of the direct-buy budgets to RTB via private marketplaces."

Denmark, Finland, and the UK were the European countries in which publishers had the highest click-through rates in Q2. Denmark and the UK were among the top in Q1 as well, while Finland had been near the bottom.

The three most popular banner formats in Q1 -- 300x250, 728x90, and 160x600 -- were tops again in Q2. The 300x250 format received 40% of all spend on RTB in Q2, and the 728x90 format received 27% of the spend.

You can download Adform's report here.