August’s Millennial Media SMART report found that nearly 30 percent of subscribers accessing retail content on their phone cannot be reached online or in-store, highlighting a new audience that retailers can reach only through mobile.

Millennial partnered with comScore to conduct research focused on mobile retail advertising, usage and growth over the past year in preparation for the upcoming holiday buying season. To reach this untapped market, it is imperative that brands double down with mobile for the 2010 holiday season. 

“There is a new retail audience that can only be reached through mobile and that means it is imperative to invest now in mobile for this holiday season or risk missing out on revenue that can only be gained through mobile,” said Erin Mack McKelvey, senior vice president of marketing at Millennial Media, Baltimore, MD.  

Mobile Web destinations such as sites and custom landing pages were the destinations leveraged in nearly 80 percent of campaigns on Millennial’s network in August.

This signals that brands are continuing their commitment to the mobile platform by creating persistent mobile Web sites and landing pages.

Expandable rich media was on the rise again in August and represented 22 percent of the campaign destination mix. 

This increase can be attributed to new advertisers, including insurance and CPG brands, leveraging the high engagement rich-media element in their campaigns to promote applications and video content. 

Millennial Media’s U.S. unique audience reach increased to 72 million unique users, meaning the ad network continues to reach more than 8 out of 10 mobile Web users.

Advertisers are continuing to engage in a deeper mobile experience with consumers. In fact more than 13 percent incorporated rich-media elements in their campaigns.

The trend of advertisers using targeted-audience campaign methods such as geo, demographic, behavioral and audience takeover, continued in August with 43 percent of campaigns on the network leveraging this method. 

Targeted-audience methods allow advertisers to engage in a deeper dialog with mobile users and the result is stronger campaign interaction rates. 

“Geo, which includes geographic location, state and international country was the targeted method of choice last month,” Ms. McKelvey said. “What is interesting about geo targeting is that it can be effectively leveraged by nearly every type of advertiser. 

“It helps global corporations appear to be more localized by providing messages custom to specific locations while also allowing small businesses and franchise locations a targeted and affordable way to drive foot traffic to their brick-and-mortar locations,” she said.