People give out a lot of personal information via social media, many would say too much information. Much of it is voluntary, and the user knows they're putting themselves out there. Filling out your profile information, tagging yourself in a photo on Facebook, or checking-in to Foursquare are all example of how people knowingly divulge personal data on the web.
But sometimes, you may be giving people a lot of information without even realizing it. And it could be as simply as mentioning a single word within a tweet.
WeKnowYourHouse.com is billed as a "privacy experiment" that pulls every tweet that mentions the word "home" and is also geotagged. I'm sure you can guess why these types of tweets could be a bit dangerous. Let's say just tweeted that you arrived home from a vacation and you've enabled location on your tweets. From those two simple factors, anyone in the world could pinpoint the exact location of your residence on a map.
Think about it: It's a stalker's wet dream.
The site owners explain how they do it, and it's frighteningly simple:
This website uses Twitter Search API to collect information, for example if you look at http://search.twitter.com/search.json?q=at+home you'll see how Twitter give away all the recent posts that match the search criteria in JSON format. We simply get the ones that contain location data (latitude and longitude) and use a geocoder to turn them into human readable addresses. Google Street View also accepts latitude and longitude into its web APIs, so we can actually see the places that people are when they tweet.
For the "experiment," they star out the user names and locations, but you can click on any entry and see a Google street view shot of where they think you live. They say that all of the entires are expunged after an hour to protect privacy, but that's just enough time for you to see how easy it is for anyone to snag the location of your home.
Of course, having the location of your house known on the interwebs isn't necessarily a bad thing, and there are plenty of other ways that a criminal or someone else could locate you. But if you're someone with a history of online stalkers, it might be better to leave the "So glad to be home!" out of your tweets.[h/t Sophos Naked Security]