Google's Android operating system U.S. market share hit 23.5 percent in October, putting it one percentage point behind Apple's iOS at 24.6 percent, according to new numbers from comScore.
Apple's iOS share was 24.3 percent in September, while Android stood at 21.4 percent. If the trend charted by comScore continues, Android should pass iOS in share by the end of the year.
The researcher also found Research In Motion's market share, though tops in the nation, continued to erode. RIM's BlackBerry OS share fell to 35.8 percent from 37.3 percent share in September.
Microsoft accounted for 9.7 percent of smartphone subscribers, down from 10 percent in September, while Palm rounded out the top five with 3.9 percent, down from 4.2 percent for the month.
The big story is how Apple's iPhone and smartphones from Motorola's Droid line and Samsung Galaxy S Android handsets continue to outsell RIM's BlackBerry devices in 2010. RIM's BlackBerry Torch and other new models haven't helped sales as much as the company had hoped.
Still, there is a lot of uncharted territory among smartphone users, which now number more than 60 million in the United States.
That means one out of every four mobile subscribers have a device sporting a full Web browser and applications. This represents great opportunity for RIM to convert feature phone users to smartphone users, provided Apple, Android and Windows Phone 7 handsets don't get there first.
Android handset sales are roiling the hardware maker waters as well, as Samsung is now the leading manufacturer of Android smartphones in the United States through the third quarter.
While Motorola vaulted Android to star status with its Droid line, Samsung made up 32.1 percent share of all Android phones sold, a 300 percent increase from the fourth-quarter 2009, when it garnered 9.2 percent Android share.
Samsung beat out Motorola, HTC and LG in Q3. The phone maker can attribute this success to its smart go-to-market strategy of offering a unique Galaxy S device for all of the major carriers.
This includes Verizon Wireless' Fascinate, AT&T's Captivate, Sprint's Epic 4G with a slide-out keyboard, T-Mobile's Vibrant and the Mesmermize on U.S. Cellular. All told, these devices accounted for more than 3 million smartphones in the United States.