Millennial Media has a new report (out this morning) that they sent along, and it's got some interesting research, based on their advertising network, about Apple and its place in the smartphone market. As you can see above, Apple's still got the majority base of OS users in the smartphone market; while we've heard that Android has pulled ahead in sales, this research shows that Apple has a clear majority in terms of actual OS usage.
Android did, however, see an increase in the number of devoted, single-platform developers. Currently, 31% of single-platform devs are working on Android (an increase of 2%) and 57% are creating apps for the iPhone. Games remain the number one app category on the network, while social networking apps are down and news and sports apps are up.
Finally, Millennial is seeing a huge spike in ad requests. Apple ad requests jumped up 36% month-over-month, and iPad ad requests alone blew up 205% month-over-month in June. Both Android and RIM saw big ad request increases as well, suggesting that more developers are learning how to successfully use ads in their apps.