Yahoo! has confirmed it has bought German software firm Actionality to boost its mobile offering for advertisers.

The deal, which has been rumoured for a couple of weeks, will give Yahoo! ownership of Actionality’s mobile marketing platform in return for an undisclosed sum.

Actionality’s software allows companies to develop mobile ads in a standardised format and insert them into a range of content, such as games.

A Yahoo! spokesperson told InformationWeek that the deal formed part of its focus on “becoming No. 1 in mobile advertising.”

Actionality chief executive Scott Cullinane told Wired:

“We’ll be continuing our business of mobile ‘around-game’ advertising, as well as contributing to Yahoo!’s broader mobile advertising strategy for publishers.”

Yahoo! inked a deal to become Vodafone’s mobile display ad partner in November last year, and has since been ramping up its presence in the mobile ad market.

It launched its oneSearch platform in January, before rolling out its mobile display technology globally in February and a set of services for mobile content providers the month after.

Google, AOL and Microsoft have also been actively expanding their mobile offering in recent months.

In May, AOL bought Boston-based Third Screen Media while Microsoft snapped up French firm Screen Tonic.

Google, meanwhile, has reported a jump in mobile users accessing its services, particularly Google Maps.