Location-based services — applications that “know” where you are and can use that information to connect you with people, places and things — are one of the hot new classes of social media applications. Basically, a location-based application allows you to check in almost anywhere on the planet and broadcast that information. Generally you can post a note, or a photo, at the same time, associating it with the location. You’ll also have the option to “cross-post” such that your location and message is published both within the application and to your Twitter or Facebook account.

Most location-based services have a few basic social networking features like finding and adding friends, and communicating with friends via private messages. You can use most location-based services on your laptop, but they are more powerful and more useful on a mobile phone, like an iPhone, Android or BlackBerry.

How Does It Know Where I Am?

There are two kinds of technology used by location-based services. The most widely understood method is through Global Positioning System (GPS) data obtained from navigational satellites in geosynchronous orbit.

The National Space-Based PNT Executive Committee says GPS has “accuracy of 7.8 meters at a 95% confidence level…(and) Real-world data show that some high-quality GPS SPS receivers currently attain better than 3 meter horizontal position accuracy.” That means under ideal conditions, GPS might know which end of the high school campus or even which classroom you’re in.

According to one source, “Nearly all new cell phones sold in America have some GPS receiving capability built in…This allows the phones to transmit a person’s location to a Public Safety Answering Point (PSAP) after dialing 911.”

That doesn’t mean all of these phones will run Foursquare, Brightkite or any other popular location-based application. Check the application developer’s site for compatibility. Foursquare, for example, runs only on iPhone and Android, though other versions are under development.

Phones without GPS, such as the original iPhone, can obtain surprisingly good location data by triangulating cellular network tower locations, known public wifi locations and even server information. With triangulation, the software can identify three known locations, and determine your position within a triangle described by these three points.

So What?

Why would you want to broadcast your location? Location is a very social attribute. Letting people know where you are tells them a lot about you, like how you spend your time, what kind of food you like, where you socialize, etc. If you go to clubs, your location can help friends find you. If you’re at a conference, friends and colleagues can coordinate schedules and get together.

I like to use location-based services to post photos of things I find amusing, like misspelled and otherwise strange signs; or to post a picture of the beach or the mountains to share some of the local sites and make others envious.

From a more practical standpoint, you could use a location-based application to keep track of a large family at a theme park, or to organize a rally.

There are many situations in which you don’t want to disclose your location, like:

• Posting your home address
• Disclosing the location of your child’s school
• Posting that you’re at the beach when you called in sick at work
• Posting that you’re at a competitor’s site

Keep in mind that everyone on the web can see your posts (unless you’ve taken steps to prevent this, in which case you’ve limited the utility of your location-based program.) As the late Canadian media theorist Marshall McLuhan said, “Publication is a self-invasion of privacy.”

Brightkite

Brightkite is the first location-based application I used. I use Brightkite and Foursquare on my iPhone, so I am describing the applications from this standpoint. They may function differently on other platforms.
Brightkite 2.0 was recently introduced, which is quite attractively laid out, and includes Twitter-inspired graphics.

Brightkite, like most of these applications, allows you to check in when you feel like it, instead of automatically tracking and posting your whereabouts. (Most users would not find an automatic system appealing, as it removes control and might raise serious privacy issues.)

With Brightkite 2.0, you tap “Check-in” and the software tries to locate you. You’re presented with a list of locations Brightkite already knows that are nearby. If your location is not on the list, you can add it. (This is a critical capability and one Brightkite did not always have.) You can post a picture and/or note in association with your check-in. Brightkite automatically creates a short URL for every check-in and cross-posts to Twitter, Flickr and Facebook, though the Facebook implementation has had some issues.

According to Brightkite, “Friends are people that you add to your friends list. Fans are people that have added you to their friends lists.” Friends are people you follow who follow you back. Fans are one-way relationships that have not been reciprocated. When you post updates to Brightkite you can post them to everyone (all Brightkite users, including fans) or just to your friends.

The Brightkite timeline is nicely laid out and emphasizes people (avatars and names) over location. Brightkite is available for iPhone, Android, and BlackBerry.

In October, Brightkite also introduced an augmented reality application, called Layar.

Foursquare

Foursquare is very similar to Brightkite in functionality with a few major exceptions. Primary among these is that Foursquare is a game. Users get points for checking in to locations, adding locations, and being the user who checks in the most often at a particular location (Update: who is recognized as the “mayor” of that location. To become mayor, a user must also post a profile picture.) As they collect points, they also get badges. The whole elaborate point system is described on Foursquare’s web site.

Foursquare does not allow users to post images, but they can post a “Shout,” which is a note, either at the same time as a check-in or separately. Foursquare does have a unique “To Do List” feature, which I haven’t found useful.

The “Tell Twitter” button always defaults to “Off,” which is generally a good thing, since some Twitter users are annoyed by excessive check-in posts.

When I first started using Foursquare, it took only a few check-ins for me to be among the top 200 users by points, which meant that not many people were using it and checking in regularly. Foursquare is also meant to be used only in a handful of major cities, like San Francisco and Montreal. I am in Boulder Creek, in the Santa Cruz Mountains, about 75 miles south of San Francisco.

When I check in here Foursquare treats it like a San Francisco check-in. When I go south about 12 miles to the city of Santa Cruz, and check in there, I get a message indicating Foursquare knows I am not in San Francisco, but suggests “Hold up! Looks like you’re not in a foursquare city right now so we’ll just pretend you’re in SF.”

Update: Foursquare now displays this message anytime I check in anywhere in Santa Cruz County. There is also a “bug” in Foursquare. When I check in at a place not in the application’s database, and that place has the same name as a place that is in Foursquare’s list, it automatically assumes I am at the San Francisco location without offering an opportunity to confirm or correct the inaccurate check-in. For this reason, I have several check-ins in Foursquare for places I have never been. If the application verified location and prohibited check-in more than say one mile from the selected location, this would fix a number of problems.)

Which brings us to “Foursquare cheating,” which involves things like employees checking in daily at a business location thus preventing consumers from achieving mayoral status; checking in while in transit; or, as one person put it, “Not even being physically there and checking in to protect a mayorship or just be a douche.”

Whenever money or points are involved, people will cheat. Tighter validation would prevent some of this, but I’m not sure it matters that much to the people who manage Foursquare. I’ve never heard of Brightkite cheating. Foursquare is available for iPhone and Android, and can also be managed via SMS.

Augmented reality and location-based services are two hot trends to watch. As Robert Scoble pointed out about Foursquare, everyone thought Twitter was lame when it started out, adding, “But I think this lame little location game is going to be bigger than Twitter.”

Another location-based application worth looking at is Gowalla, which I haven’t had a chance to check out. (If you use Gowalla, please share your experience with a comment below.) Brightkite, Foursquare, Gowalla and Layar are all available from the iPhone app store.

This post was updated 11/11/09

Tags: Location-based services, Brightkite, Foursquare, Gowalla, GPS, triangulation