February was the first time smartphone owners accounted for half of all mobile phones in the United States, according to new data from Nielsen.

Purchases of new smartphones remain strong, suggesting that at some point this year, there are likely to be more consumers owning smartphones than features phones. The results have important implications for marketers, as smartphones offer more opportunities as well as more robust ways to reach consumers with brand messaging.

?The trend is definitely showing that smartphone ownership is on a strong trajectory to surpass half of mobile phone users this year,? said Jonathan Carson, CEO for digital at Nielsen, New York. ?Since mobile and media technologies evolve rapidly, there may be new consumer trends that help accelerate this trend in the coming months.

?The increase in smartphone use has broad implications for marketers,? he said.

?As mobile app usage continues to skyrocket and mobile media consumption ? from video to location-based content ­continues to rise, there are infinite possibilities for marketers, both in terms of more advanced platforms to reach consumers, and more opportunities to be creative with when and how marketers can reach their audience.?

Two-horse race
According to Nielsen?s data, 49.7 percent of U.S. mobile subscribers owned a smartphone as of February. This is a 38 percent increase over February 2011, when only 36 percent of mobile subscribers owned smartphones.

The growth is being driven by smartphone adoption, with more than two-thirds of those who have acquired a new mobile device in the last three months choosing a smartphone over a feature phone.

The numbers also point to what is increasingly a two-horse race between Android and iOS in the smartphone market.

Android continues to lead, with 48 percent of smartphone owners saying they owned an Android device in February. IPhone owners accounted for 32.1 percent of smartphone users, and BlackBerry owners 11.6 percent. An additional 8 percent owned some other kind of smartphone.

However, Apple?s numbers improve among recent acquirers with 43 percent of those who purchased their smartphone within the last three months having bought an iPhone. The numbers reflect the popularity of Apple?s newest iPhone model, the 4S, which was introduced in the fall and sold four million units during the first weekend that it was available.

Among recent acquirers, 48 percent purchased an Android phone, five percent a BlackBerry and four percent some other kind of smartphone.

BlackBerry parent company Research In Motion recently reported that its smartphone shipments declined 21 percent during its recent fiscal fourth quarter and that it plans to focus on trying to recapture sales in the enterprise market going forward.

?Android devices and iPhones are certainly capturing a significant portion of the smartphone market at this point, but the mobile landscape is dynamic and always changing and new competitors can rise at any time. What is certain is that smartphone adoption is on the rise,? Mr. Carson said.