Apple?s iPhone is the leading smartphone by impressions, representing 15.1 percent of impressions, according to Millennial Media?s most recent report.

Millennial Media?s Mobile Mix report broke down which devices and manufacturers on the ad network for the first quarter of 2012. Although Apple is top dog in manufacturer impressions, Samsung is close on its heels with 18.25 percent.

?We saw a significant increase in impressions from non-phone connected devices in 2011, and this was another proof point of how tablets are impacting the mobile landscape,? said Mack McKelvey, senior vice president of marketing at Millennial Media, Baltimore, MD.

?Consumers have embraced tablet devices, and advertisers are reacting in turn,? she said.

New offerings
Although the iPad is still a force to be reckoned with in the tablet industry, other devices such as Amazon?s Kindle Fire, Samsung?s Galaxy Tab, Motorola?s Zoom and BlackBerry?s Playbook are also beginning to play an important role for mobile advertisers.

All five top tablets placed within the top twenty for mobile devices, showing the shift to more tablet advertising.

With tablets expected to reach 198 million shipments by 2016, according to the International Data Corporation, the devices are increasingly being seen as separate from smartphones.

Non-phone connected devices made up 20 percent of Millennial Media?s impressions, representing a 33 percent quarter-over-quarter growth.

Smartphones accounted for 73 percent of impressions and feature phones claimed seven percent of impressions.

To compare, in the first quarter of 2011, 62 percent of impressions came from smartphones, 23 percent came from feature phones and 15 percent came from non-phone connected devices.

For operating systems, Android claims 49 percent of impressions. IOS devices made up 33 percent of impressions, BlackBerry made up 14 percent, Windows generated three percent and the Symbian operating system represented one percent of impressions.

Besides Apple and Samsung, other top manufacturers included HTC, Motorola and Research in Motion.

Fifteen out of the top 20 phones on Millennial Media?s platform are Android-operated, showing the fragmentation of the operating system.

Samsung devices represented four of the top 20 mobile phones.

Millennial Media claims that the company has run more than 10,000 campaigns on the platform to date.

Rich features
Advertisements that included a mobile video on Millennial Media?s platform increased 958 percent year-over-year, per the study.

Additionally, gaming apps claimed the top spot app category, growing ten percent quarter-over-quarter.

Music and entertainment apps came in as the No. 2 app category on Millennial Media?s platform.

Other top categories included sports, social media, news, weather and health and fitness apps.

?Impressions on sports apps almost doubled quarter-over-quarter, and as a category, sports was No. six in our top mobile application categories,? Ms. McKelvey said.

"As our recent March Madness report with the IAB showed, specific sporting events present an exciting opportunity for advertisers, and this definitely came through on our platform,? she said.

Final Take
Lauren Johnson is editorial assistant on Mobile Marketer, New York