Last year Pew and Forrester both came out with reports arguing that LBS check-ins (e.g., Foursquare) were being embraced by only a small fraction of the mobile audience. In July Forrester asserted that "geolocation applications like Foursquare" were only occasionally being used by 4% of all Internet users.
In November Pew released findings from a telephone survey (n=3,001) that argued a similar 4% of PC Internet users and 7% of mobile Internet users were on LBS services. However 4% of online adults actually turns out to be a big number. It's roughly 8 million people, using the ~200 million online audience base of comScore.
In the aggregate, in 2010, there were probably several million people in the US checking in on Foursquare, Gowalla, MyTown, Whrrl and others, including Google Latitude.
Today Foursquare says it has 8.5 million users alone and many others, including Yelp and Facebook, offer check-ins. Facebook has not released official numbers but claims it is "by far" the largest check-in site out there. So the numbers are clearly growing.
ComScore released data yesterday asserting that, now, nearly 17 million mobile users are engaged to some degree with "check-in services":
16.7 million U.S. mobile subscribers used location-based “check-in” services on their phones in March 2011, representing 7.1 percent of the entire mobile population. 12.7 million check-in users did so on a smartphone, representing 17.6 percent of the smartphone population.
ComScore defines this category to include Facebook Places, Foursquare and Gowalla. It's unclear what the full list of sites was or whether beyond a couple of examples, the definition of check-in sites was left up to user interpretation.
As one might expect smartphones were the primary source of check-ins, constituting 76.3% of all usage. Here's the smartphone "check-in" OS breakdown:
Overall comScore says that these check-in 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."
One surprise according to the survey data is that women overall outnumber men on check-in services, in contrast to last year's Forrester findings that showed a wide gap favoring men.
Anecdotal evidence, notwithstanding the growth comScore proclaims, suggests that a large number of early users of check-in services have walked away and are no longer using them on a regular basis.
Deals and loyalty programs -- such as one just announced between SPG and Foursquare -- are the key to keeping check-ins alive. In the absence of such rewards or incentives the check-in will either die or have to dramatically evolve and deliver some other type of value to survive.