More than half of smartphone ads appear on the Apple OS, according to figures from Millennial Media, but Android is catching up fast.
In its report, Millennial says Apple holds 55 percent of smartphone ads, followed by Android phones with 19 percent, RIM with 16 percent and Windows Mobile with just four percent.
Android has become the second largest OS on Millennial's platform for the first time since the company started reporting figures a year ago.
But developers are playing the field, says Millennial. The company says that a full 100 percent support Apple's iOS, but that 75 percent also support Android and 46 percent RIM's Blackberry OS. Twenty-nine percent support Symbian, and 21 percent Java.
"The fact that more devices are being launched by the different handset manufacturers and the fact that developers are choosing to develop on multiple platforms, continues to show that where there is money to be made, developers will go there," says Steve McCord, head of product development at Millennial.
"In addition, it shows that the larger the reach for any one particular application, the higher monetization growth opportunities that affords them."
Millennial Media is now the largest independent mobile advertising network, following Google's acquisition of AdMob and Apple's takeover of Quattro Wireless. Millennial, too, may not remain independent for long, having recently entered into talks with RIM about a possible takeover.
While RIM is reported to have baulked at the price, there may well still be some sort of takeover deal to be struck for Millennial in future.