U.S. online advertising spending will nearly double to $35.4 billion by 2012, with search and display advertising accounting for the lion’s share of expenditures, according to Jupiter Research. It pegs total online ad spending at $19.9 billion in 2007. Major drivers include explosive growth in display inventory, increased paid click volume, and better targeting technology. “The rapid growth of social sites online has accounted for considerable growth and availability of inventory now available to advertisers,” said Jupiter Research analyst Emily Riley. “Today, inventory on social sites is fulfilled largely through ad networks and contextual advertising, but as they mature, they will begin to use tactics such as behavioural targeting that allow for better monetization of their inventory.” Jupiter Research found static image and text advertising will be the most popular display formats in 2007, comprising over two thirds of online display revenue. It expects new publishers will continue to improve their advertising mix and will shift towards more lucrative rich media and video formats over the next few years.