5. Young folks don't watch broadcast content.

We've heard the dire statistics: TV viewing has dropped among the teen and adult demographics, especially among men. But there is still appointment television, although it might be time-shifted slightly, Kirby says. People want to be able to join in the conversation at school or work about last night's shows, so they'll watch "Gossip Girl" on Monday night and "The Office" on Thursday night -- but they may TiVo through the commercials or watch it after another show. They may watch on the big screen downstairs, the small TV in the bedroom or their computer screens at home or elsewhere.

"The key to connecting with them via TV and video content is relevance," Kirby says. That means both message relevance and relevance of the content where the ads appear, whether online or off, is critical.

The media multi-tasking that young people do only adds to the confusion. While neuroscience indicates that people can't really pay attention to two things at once, the distractions of instant messaging, talking on the phone or Facebooking make the media task more challenging.

Kirby says it's important to play to the consumer's likely mindset on any one of the media channels and present brand ads on the engagement medium. For example, say someone is watching the World Series while he's logged into MLB.com and texting friends with score updates. The TV is used as entertainment, while he's using the internet to find information that deepens that entertainment experience. "So, that is the engagement," Kirby says. "Texting is a task. You wouldn't want to be interrupted in that task with a message."

According to Hadley, marketers should surround the consumer with relevant messaging that takes into account the interplay between the different media and devices. "The historical purchase path was very linear," he says. "Now, it's a tumbler."

6. Digital media planning and buying are separate roles.

This is another holdover from the traditional world, digital media execs say. But it just doesn't work when it comes to online.

"In digital, you have to plan and buy at same time," Samples says. "While you plan, you're also in negotiation. It all has to happen in an integrated approach."

Besides, we now know that digital is a gargantuan branding tool, says Koerner. "In order to execute a strategy, you have to be involved the entire way," he says. "Digital is not a function of just making the buy; you have to optimize and negotiate based on a strategy. So, there's no way I could be convinced that you would want to separate those factions out."