Dive Brief: 

• Independent ad server OpenX, a distant second to Google, was built for traditional display ads, but is beefing up efforts for mobile. 
• The firm recently hired four mobile executives and has plans to double its total number of mobile employees from 30 to 60 to support its expansion into the format. 
• According to President John Gentry, the fact that audiences will be viewing content on multiple screens is "inevitable," so it would be foolish to ignore the shift to mobile even though advertising dollars haven't quite caught up with the user numbers yet. 

Dive Insight: 

OpenX is making a huge investment in mobile that isn't likely to pay off for a while — or at least until more ad dollars start to roll in around mobile. However, like Mr. Gentry said, it seems that users are migrating to mobile in droves and the ads of the future will have to adapt to multiple screens.