Do you share your location on social networks like Instagram and Twitter?
Modern smartphones make it simple to embed your physical location in a tweet, or tag your GPS co-ordinates to a new snapshot you post.
Perhaps the following video will convince you that this isn't such a good idea.
American comedian Jack Vale took to the streets of Irvine, California, with nothing more than a smartphone.
With that, he was able to search for social media users nearby who were posting messages - and then FREAK THEM OUT by telling them their names, and personal information about themselves.
As you can see in the video above, some of the social media users aren't just mildly creeped out by a complete stranger knowing about their private lives, their response is anger.
Someone who knows your location might rob your house while you're on holiday, or stalk you.
But it was ultimately their choice to share the information, and their location, on social networks.
So, here's my guide on how to stop sharing your location with strangers.
You might choose to change your account settings, so your Instagram posts and videos are treated as private, and only shared with your approved followers.
You do that by choosing Edit Your Profile, and ensuring that "Posts are Private" is enabled.
Go to the Twitter website, log into your account and visit Settings > Security & Privacy. There you will find the option to add your location to tweets. Make sure it is disabled.
Twitter also gives you an easy way to wipe location information for tweets you have made in the past.
You may want to also examine the settings of your third-party Twitter app as well, to check that they aren't putting your privacy at risk.
Further than that though, you could disable location services on your smartphone so Instagram (and other apps) can't tell where you are.
iPhone users can turn off location services by going to their smartphone's Settings app, and choosing Privacy > Location Services. Either disable Location Services entirely (which you may find inconvenient) or scroll down to Instagram and set it to "off". You can do the same with your particular Twitter app.
Android users have their location determined by a variety of technologies (GPS satellites, WiFi hotspots and your proximity to cellphone network towers). You can disable Android's location services by choosing Settings > Location services and disabling Google location services and GPS satellites. Of course, you may not find this a practical solution to the problem.
And, bear in mind, that if you disable location services *entirely* on your smartphone, you won't be able to take full advantage of maps and "find my smartphone"-style services when you misplace your device.
Be careful with photos too. Photos taken on your smartphone might contain EXIF meta-data which includes your GPS co-ordinates. Anti-virus veteran John McAfee fell foul of just such an EXIF geo-tagging screw-up while on the run in Central America.
Ultimately, you have control over what you share on social networks. If the social network doesn't give you an easy way to prevent publication of your location - maybe you should rethink your use of that social network, or not be surprised if strangers know more about you than ever imagined would be possible.
At the very least, be very careful what you post - and what details you are sharing with the online world about your location and private life.
If you are on Facebook, and want to be kept updated with news about security and privacy risks, and tips on how to protect yourself online, join the Graham Cluley Security News Facebook page.