From Twitter to tablets, cameras to mobile phones, geolocation services are everywhere. And if you just want to record exactly where you took a set of holiday photos, then that’s fine. But, of course, there are privacy implications.

And a new program called Creepy shows just how serious they can be, by attempting to locate anyone through their tweets or web images.

Give the tool a Twitter or Flickr user name and it’ll go to work, using Twitter’s own tweet location information, geolocation data from image hosting services, the EXIF data in any photos it finds, and more. And if it finds any locations then they can be displayed on Google Earth, Virtual Earth or OpenStreetMap, or exported as a KML or CSV file.

This approach can be scarily powerful. You might be very careful with your geolocation permissions, turning the technology off in Twitter and all your devices, but if you make a single mistake – or, say, post a photo taken by a friend who isn’t careful at all – then that’s all it takes. Suddenly a simple photo of a birthday party, for instance, might give away your home location to anyone who makes the effort to look.

But does it work? Right now Creepy is still in its very early stages. Searching occasionally fails with API errors, sometimes the program hangs for no apparent reason, and if you’ve a slow internet connection then searches can take forever anyway (it may have to download thousands of tweets, and many images to check for EXIF data).

And yet, using the program to check up on some of Twitter’s more famous users did occasionally turn up positive results. Entering aplusk (Ashton Kutcher) returned a few New York locations; BillGates gave his Long Beach position away in one tweet; and searching the tweets of British actor and author StephenFry worked best, returning no less than 156 locations from various places where he was filming around the world.

These were exceptions, though – our initial tests found Creepy returned useful positional data for roughly 15% of searches. That’s hardly spectacular, but the program can only become more powerful in future: the author is already working on adding support for searching additional services, and as the project is open source then others are free to join in.

Try out the program on your Twitter or Flickr account, then, just to see how much information you might be giving away. And if you’re not sure how you might have geolocation set up right now, then take a look: check Settings > Account > Tweet Location in Twitter, Settings > Locations on iOS devices, or browse the settings in your Android apps. In the latest Camera app, for instance, click the wrench icon, look for the “Store Location” setting, and turn it off to take position-free photos in future.