The Pew Research Center’s Internet & American Life project found that 4% of online adults use a location-based service such as Foursquare or Gowalla. These services allow users to share their locations with friends and find. According to the Pew study, on any given day, 1% of internet users are using these services. 
4% of online Americans use location-based services
Why is this important to jouranlists? Partly this is a growing trend of online users. And partly it is all about who are using the services.
One quick glance at the table and it is clear that Hispanics outnumber other ethnic groups. There has to be a reason for that.
The growth in this fairly new addition to online mobile applications comes as more adults are using other services such as mobile Twitter and Facebook to record their locations and activities.
Accroding to the Pew report:
Internet users who use social networking sites such as Facebook or MySpace and those who use status-update services such as Twitter also have relatively high levels of location-based service usage:
Among online adults, 62% use a social networking site such as Facebook, MySpace, or LinkedIn. Of these social networking site users, 6% use a location-based service.
24% of online adults use Twitter or another service to share updates about themselves or to see updates about others. Ten percent of these status update site users use a location-based service, over twice the rate of the general online population.
Knowing how people use and view social networks can be a big help in developing and reporting stories. It always pays to understand what is going on.
UPDATE
And just in case you were wondering why or if you should be interested in how and where people use social networks and location-based services, take at look at this report from the AP:
In social media election, the GOP capitalizes
For an entity that effectively didn't exist just years ago, social media has rapidly flourished as a political force.
"This is the election when it became more deeply embedded in the rhythms of campaigning," says Lee Rainie, director of the Pew Internet and American Life Project. "It's not so much that as a single thing it influences people's votes but that it's now so inextricably a part of the political communication landscape."