If you've used that Facebook 'most used words' app you should probably worry

'Star', 'Wars', 'football', 'cat', 'videos', 'burgers', 'space' - we know what ours are, how about you?

Yes, pretty much everyone we know has completed and shared that 'Most Used Words' quiz on Facebook, but there's a small problem with it: it's not actually made by Facebook.

And, as such, everyone who's used it has inadvertently handed over a host of personal data - including their name, profile picture, posts and likes - to the makers of the app, South Korean company Vonvon.

Tech expert Paul Bischoff, writing on Comparitech says: "Vonvon is free to sell your data to whomever it pleases for a profit. Vonvon says it will not share personal information with third parties without permission, but just by playing the quiz you’ve technically given it permission."

As well as personal data, the app can access technical data about the computer being used, including its IP address and the browser being used, both of which can be useful in stealing further personal information. Bischoff describes the whole situation as a "privacy nightmare", adding that "over 16 million people have agreed to give up almost every private detail about themselves to a company they likely know nothing about just to play a quiz".

The company has responded to the article, denying that it has any plans to use the data nefariously, saying: "There are some false rumours that we are trying to capture people's information so we can sell it to third parties. We don't really get any meaningful information when people uses our apps. And when they share it on their walls, it really doesn't have much information about them. People look at it as something fun. Most people just try to have a good time with it."

You can read the response in full here - but, even if Vonvon isn't evilly plotting to take over the world, it demonstrates how easy it would be for someone else to.