Almost 1 in 5 smartphone owners in the US access check-in services via their mobile device, according to the results from a study of mobile social networking check-in service users based on data from comScore’s MobiLens service.

The study found that 16.7m US mobile subscribers used location-based check-in services on their phones in March 2011, representing 7.1 per cent of the entire mobile population. 12.7m check-in users did so on a smartphone, representing 17.6 per cent of the 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,” says Mark Donovan, comScore’s senior vice president of mobile. “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.”

Check-in service users, defined as those accessing services such as Facebook Places, Foursquare and Gowalla, had heavy skews toward 18-24 year olds (26.0 per cent) and 25-34 year olds (32.5 per cent) in relation to both the total mobile audience and the overall smartphone audience. They were more likely to be full-time students (23.3 per cent) when compared with total mobile (14.6 per cent) or overall smartphone users (16.5 per cent).

Nearly half (46.4 per cent) of check-in users were employed full time, slightly less than the percentage of smartphone users who were employed full time (53.3 per cent). Both check-in service and smartphone users were more likely to be employed full time than overall mobile users (38.9 per cent).

Of the 16.7m people using check-in services on their mobile devices, 12.7m (76.3 per cent) did so via a smartphone. Android accounted for the largest share of check-in service users, with 36.6 per cent checking-in from an Android device.  33.7 per cent 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 per cent of check-in service users, while Microsoft, Palm and Symbian each accounted for less than 5 per cent.

When compared with an average smartphone owner, social networking check-in users were more likely to access mobile media across a majority of content categories. More than 95 per cent of check-in service users used their mobile browser or apps. Nearly 62 per cent accessed news. Check-in user behaviour was also consistent with that of traditional early adopters, with 40.3 per cent of users accessing tech news, and 28.2 per cent owning a media tablet, both significantly higher than average.

Check-in service users also showed a high propensity for accessing retail-related destinations on their mobile devices. Nearly one-third of users accessed online retail sites on their mobiles, while one-fourth accessed shopping guides. Check-in service users were also more likely to be exposed to mobile advertising, with nearly 40 per cent recalling seeing a web or app ad during the month, compared to just 27.5 per cent of smartphone users.