• by Laurie Sullivan  @lauriesullivan, July 18, 2013

Marketers spent 16% more on paid-search campaigns in Q2 2013 compared with the prior year, but the cost per click continues to rise across engines, according to a report released Thursday.

Across the board, The Search Agency clients reduced the amount spent on desktop campaigns by 12.5% YoY in Q2 2013. Smartphone and tablet investments rose by 70.4% and 74.7%, respectively.

On Google, the average CPC across devices rose 8.3% YoY and 21.2% sequentially for The Search Agency clients, while the average CPC on Bing rose 18.9% YoY and remained relatively flat sequentially.

The click-through rate (CTR) fell across all devices on Google. Desktop CTR by 6.8% YoY and 24.1% sequentially; smartphone CTR, 15.6% YoY and 16.2% sequentially; and tablet CTR, 23.8% YoY and 26.2% sequentially.

Results tell a little different story on specific devices. Desktop CPCs on Google rose year on year and sequentially, 9.6% and 20%, respectively. Smartphone CPCs fell 4.9% YoY, but rose 23.8% sequentially. Tablet CPCs rose 25.3% YoY and 27.8% sequentially.

On Bing, desktop CTR rose 12.2% YoY, but fell 18.2% sequentially. Smartphone CTR decreased dramatically, by 27.2% YoY and 28.2% sequentially. Lastly, tablet CTR dramatically increased YoY, up 120.9%, but remained flat sequentially.

Desktop CPCs on Bing rose 21.9% YoY and 1.1% sequentially.Smartphone CPCs fell 3.7% YoY and 13.8% sequentially. Tablet CPCs rose 8.9% YoY and remained relatively flat sequentially.

Among The Search Agency clients, Google's click share fell to 86.9% in Q2. The engine's share of impressions, compared with Bing's, rose 3.1% to 77.1% in Q2, YoY, and by 1.1% sequentially. Advertisers also spent less on Google, with the amount falling 2.5% to 83.8% in Q2, compared with the prior year.

It's clear that consumers continue to increase searches on smartphones. Google's share of impressions by device among The Search Agency clients changed dramatically during the past year. In Q2 2013, Google held 75.3% of impressions' share on desktops, 13.7% on smartphones, and 11% on tablets, compared with the year-ago quarter. In Q2 2012, Google held 87.8% share of desktop impressions, 6.1% on smartphones, and 6% on tablets.

Bing's share of impressions by device among The Search Agency clients also changed dramatically. Q2 2013 Bing held 87.5% on desktop, 8% on smartphone, and 4.4% on tablets. In Q2 2012, Bing held 93.5% on desktop, 3.1% on smartphones, and 3.3% on tablets.