NEW YORK -- Mobile is cannibalizing parts of the Web and taking them on the road, according to Paul Palmieri, president/CEO of Millennial Media.

Mr. Palmieri spoke at the Mobile Marketing Association's Mobile Marketing Forum in the Grand Hyatt Hotel. His solo session was titled, "The Growth of the U.S. Mobile Interactive Advertising Business."

"Weather is not the only category that is seeing a significant amount of the audience preferring the mobile channel, but if you are selling an over-the-counter flu medication, and you traditionally buy weather sites online" mobile now must be a big part of your digital spend," Mr. Palmieri said.

So what is the consumer doing when they are reached on their mobile device?

Mr. Palmieri moved on to talk about the behaviors of mobile consumers in the U.S.

He said that American mobile consumers are seeking and finding an explosion of content experiences across a range of devices, are receptive to advertising messages and are in many cases in close proximity to making a purchase decision.

"Think: downstream of the yellow pages and upstream of a coupon," Mr. Palmieri said. "Unlike the geriatric calisthenics that the web uses to describe their audience, mobile consumers are neither leaning back nor leaning forward. They are on the move."

Forty-six percent of consumers that are reached on their mobile phone are accessing device applications and 54 percent are viewing ads as a result of browser actions.

Therefore, it is safe to say that consumers are doing lots of things as a result of campaigns.

Mr. Palmieri then covered the costs around getting one consumer to take one action.

"At Millennial, we call this metric: cost-per-engaged-user or CPEU," Mr. Palmieri said. "We report this metric each month in our SMART report, and if you are familiar with online, you can clearly see by these numbers -- that mobile can be a huge driver of back-end brand metrics.

"We also break out the CPEU by targeted method so that you can understand the metric in deeper detail," he said.

Media planning in mobile is very similar to online, according to Mr. Palmieri.

Millennial Media has an internal media-planning tool that it uses to build plans for its clients.

The company found that mobile media is targeted by various tracking methods. Channel, demo by index by sub-universe, takeover, demographic and audience are among some of the most popular targeting methods.

Rich media is emerging as more handsets begin to be able to accommodate expandable, carousel, in-banner video.

Mr. Palmieri showed used Kraft Food's iPhone application as an example.

The branded app was created by Point Roll.

"Rich media is happening faster in mobile than it happened online, and the same goes for advanced targeting," Mr. Palmieri said.

He then moved on to talk about how fast advanced targeting will move into mobile.

The formation of persistent audiences based on a number of factors began last year, but is in use in earnest in second quarter of this year.

In terms of categories of spend, Millennial Media has seen strong spending in entertainment, mobile downloads and CPG as one would expect, but also categories that take advantage of the immediacy and geo effect of mobile like travel and retail.

"That was a lot to throw out there, but I hope some of this information is as exciting to you as it is to us," Mr. Palmieri said. "So, if you are an agency and you are spending -- congratulations and thank you.

"Mobile is not daunting, it is easy to plan, buy, target and measure," he said.