Online advertising will more than double to $50.3 billion in 2011, from $21.7 billion in 2007, mostly driven by new technologies that boost online ad performance, according to the research firm Yankee Group.

“While the size of the U.S. Internet audience will level off in the next few years, ad dollars have yet to catch up with the growth in online media consumption,” the Yankee study said. The Internet accounts for about 20 percent of total media consumption, but only 7.5 percent of ad budgets.

The Internet ad share is expected to double to about 15 percent in three years, closing the gap with television. Marketers will spend three-quarters as much per online user as TV viewer ($244 versus $313) by 2011; while in 2006, advertisers spent less than one-third as much online as TV per user ($89 versus $276), Yankee Group reported.

According to the Media Post article, helping drive the online ad shift will improve ad targeting, and the "yield management," which focuses on maximizing revenue without upgrading ad inventory.

"We've thought of this as an industry in which advertisers are the ones in the driver's seat, but it's clear that publishers have a lot they can do as well," Daniel Taylor, senior analyst at Yankee Group said, according to Media Post. He also pointed out a prediction of 24-percent annual growth rate for online advertising throughout 2011.

That means investing in new online media formats such as video, gaming and virtual worlds and creating marketer segments that go beyond just direct response and brand advertising. While more refined targeting techniques will help improve revenues, publishers also need to be mindful of users' privacy concerns.

The Group, in addition, encourages advertisers and agencies to invest in technologies to integrate interactive budgets into mainstream planning and buying activities. "This is a technology-driven marketplace and agencies should be using technology to manage it," Taylor added.

Yankee also recommends advertisers to double online ad budgets each year, and take advantage of video and mobile ad opportunities. "The reality is it takes time, and this market is just about reaching adolescence now," Taylor said.