At the end of 2012, Apple still led with a 31.2% share. Samsung was second with 22.3%.
FORTUNE -- Millennium Media, the No. 3 mobile advertising platform after Apple and Google, issued its 2012 year in review report . A few highlights:
- Although it lost market share in 2012 in terms of the number of smartphones and tablets sold, Apple is still the No. 1 manufacturer in Millennium's ad platform and actually gained share (to 31.2% from 26.35%).
- Samsung came in No. 2 for the second year in a row. Although it grew faster than Apple (to 22.32% from 16.8%), its presence on the Web in terms of ad impressions is not keeping pace with its growth in units shipped.
- Amazon made it into Millennium's top 15 for the first time in 2012. Its 1.08% share put it in 11th place.
Among the top 20 mobile phones, the iPhone was the leader with 16 percent of all ad impressions. But eight Samsung phones scored a spot on the list, more than any other manufacturer. Collectively, those eight phones grabbed more than 13 percent of all impressions. Among other device makers, HTC took third place with a share of 7.96 percent, followed closely by Research-in-Motion with 7.9 percent.
Looking at mobile operating systems, Android made up 52 percent of all impressions on the ad network.
Apple's iOS took in 34 percent, unchanged from the prior quarter. However, iOS 6 gave Apple a shot in the arm.
Android and iOS virtually own the mobile marketplace, leaving other operating systems with tiny pieces of the pie.
For the third quarter, RIM's BlackBerry OS snared 8 percent of all ad impressions, down from 15 percent the prior quarter. Microsoft's Windows Phone eked out 5 percent, a small gain from 4 percent in the second quarter. And Nokia's Symbian stayed flat with a 1 percent share.