Tablets could be responsible for as much as 20 per cent of Google’s paid for search ad clicks in the US in 2013, which considering the company reported advertising revenue in 2012 of $46bn, could be a very big number.

Paid for search ad clicks are Google’s biggest revenue generator, and tablets could be the new battleground in this area, according to statistics released by digital advertising specialist Marin Software this week.

Tablets are forecast to drive 20 per cent of Google’s paid search ad clicks in the US this year, up from 10.7 per cent in 2012 and 6 per cent in 2011.

Marin predicts the conversion rate of search ads originating from tablets will eclipse those of desktops before year end, rising 31 per cent, while the conversion rate on smartphones will increase just nine per cent and desktops just seven per cent.

In addition to rising conversion rates, Marin found tablet ads have favourable performance characteristics relative to desktop ads with click-through rates for search ads on tablets 37 per cent higher than ads placed on desktop searches. The average CPC for paid-search ads on tablets was 17 per cent lower than that of desktops in 2012.

Marin found that the share of search ad spend directed towards tablets grew from 4.8 per cent to ten per cent in 2012 with spend on tablets eclipsing smartphones for the first time in Q4 2012.

“While the rise of tablets is no secret, what’s interesting is tablet users are engaging with search ads and converting in ways that closely resemble desktop usage,” said Matt Lawson, VP of marketing and partnerships at Marin. “Solid user engagement combined with favourable performance characteristics make search ads on tablets hard to resist for advertisers.”