Nearly one in five US smartphone owners use their device to access ‘check-in’ social networking services such as Foursquare, Facebook Places and Gowalla, according to a new study by digital measurement firm comScore. The study found that 16.7 million US mobile subscribers used location-based ‘check-in’ services on their phones in March 2011, representing 7.1 percent of the entire country’s mobile population. 12.7 million check-in users did so on a smartphone, representing 17.6 percent of the US smartphone population.

The study also found that check-in service users showed a high propensity for mobile media usage, including accessing retail sites and shopping guides, and displayed other characteristics of early adopters, including a stronger likelihood of owning a tablet device and accessing tech news, when compared to the average smartphone user.

“Although still in their relative infancy, location-based mobile check-in services are seeing rather impressive adoption among smartphone users,” said comScore’s Mark Donovan. “The ability to interact with consumers on this micro-local level through special offers, deals and other incentives provides brands with the real-time opportunity to engage consumers through their mobile device.”

Android accounted for the largest share of check-in service users with 36.6 percent checking-in from an Android device, while 33.7 percent of users checked in from an iPhone, with Apple having the highest representation relative to its percentage of the total smartphone market (Index of 132). RIM accounted for 22 percent of check-in service users, while Microsoft, Palm and Symbian each accounted for less than 5 percent.

The study also found that those in the 18-34 age bracket accounted for nearly 60 percent of total check-in service users.

  % of Smartphone Users % of Check-In Users Index
Total Smartphone Audience: 13+ yrs old 100.0% 100.0% 100
Android 34.7% 36.6% 105
RIM 27.1% 22.0% 81
Apple 25.5% 33.7% 132
Microsoft 7.5% 4.3% 57
Palm 2.8% 2.0% 72
Symbian 2.3% 1.2% 51

US ‘check-in’ service users by smartphone platform (3-month avg. ending March 2011)

Source: comScore MobiLens