Millennial Media released their third quarter marketing research data. Their data reflects the number of ads/impressions that are viewed on mobile devices. This criterion obviously gives more of an indicator of how much a device is used as opposed to how many there are out there, but it is still statistically significant for judging the relative growth of a product. Apparently, ads/impressions for Android devices doubled over the number of iOS devices. This is based on the quarter that ended last month, and shows that Android accounted for 56% of impressions. As you can see from the pie chart, Apple had 28%, while RIM dropped to a paltry 13% share, with Microsoft and Symbian sticking to their minimal 1%.

If you rank specific devices or manufacturers, instead of Operating Systems, things look different with Apple's iPhone topping a couple of lists. It's interesting to note how many folks are still using older devices, but not really surprising in retrospect. Here are some more lists below:

Source: BGR and Millennial Media