Screenshot from Geosocialfootprint.com
The downsides to using Twitter’s geo-tagging, where each tweet gives out your location, seem pretty clear: Any creep knows where you are.
Providing one's location is obviously the reason why people opt in for geolocation tagging on their Twitter account, but it may not occur to them just how much they are giving away and to how many people. To raise awareness, Chris Weidemann developed the application Twitter2GIS. Users can test their—or anyone’s—Twitter handle at GeoSocial Footprint to see what they’re showing to the world.
Weidemann is a graduate student in the Geographic Information Science and Technology online master's program at the USC Dornsife College of Letters, Arts and Sciences, and also works for the federal government managing a team that builds geospatial systems. With Geosocial Footprint, Weidemann said his “intent is to educate social media users and inform the public about their privacy.”
Because beyond opting in to attach GPS data, another 2.2 percent of all tweets—equating to about 4.4 million tweets a day—provided so-called "ambient" location data, where the user might not be aware that they are divulging their location. Weidemann gave this example: say you tweet with a GPS tag that you're happy to be home to watch some TV—you've just indicated "home."
But even if geo-tagging is off, you could be giving yourself away through "natural language geocoding," wherein the content of your tweet gives you away even if GPS doesn't. "An example of this may be '@bestfriend I'll meet you at Ai Fiori for dinner,'" said Weidemann. All you need to do then is search where Ai Fiori is. If the tweeter has some GPS data, you can even narrow it down your results closer. Twitter profiles are specifically designed to give away at least some data by requesting that you list your city and time zone, which could be enough.
Between geotagging and geocoding, up to about 35 percent of tweets containing some user location data, according to Weidemann's estimates.
Right now, GeoSocial Footprint only tests the last 200 tweets for GPS data, but Weidemann plans to expand to include clues that "geo-coded" tweets throughout one's entire Tweeting history.
I tested it out, and was happy to see that my sparse, impersonal tweet style doesn’t give away much about my personal life. I sent an email out the Motherboard contributing list, and the majority of contributors weren’t giving anything away either, although a few mentioned that if "geo-coded" tweets were included they'd definitely be at risk.
The exception was contributor Dan Stuckey, who turned geo-locations on kind of academically to explore the intersection between his physical location and his Tweet content, but didn’t feel like he tweeted enough for it to be useful or dangerous.
So naturally, I just started plugging in other Twitter handles. Barack Obama’s was safe. Gwyneth Paltrow, clean. Paris Review. Still nothing.
Bill Nye, California Guy
Then I plugged in Bill Nye and got what I think is his house, with an Earth flag and beautiful desert-flora lawn. So there’s some stalker potential in the app, but it’s only using information that the Twitter user volunteered already, perhaps unwittingly.
I told Weidemann and he forgave me for stalking the Science Guy, saying, "My end goal is to educate and inform the general public of these risks. Just like anything, it could be used for good and bad, but in reality it's all publicly available data—and that's the ultimate point I'm trying to make."
There’s reasons that geo-location tagging is useful—researchers have used tags to determine people’s moods in various locations in New York, and the more information Twitter can collect on you the more valuable your profile becomes for marketers—but I don’t really see the upside for the actual user volunteering this information.
Weidemann doesn't see Twitter coming forward to explain the risks of location data any time soon, even if he wishes they would. "While I understand their business motives, I just wish they'd try harder to educate the users on over sharing (both location and non-location over sharing)," he said. "Since they're not going to, this [application] seems like a good means for doing so."
Because even if you don't care that your location data is out there, someone else is paying attention. "If social media providers are going to use this public data, along with large enterprises, and the intelligence community—all to profit off us—we as users should have a tool to view and manage our own location footprints," Weidemann said.