The privacy police have spoken. If you live in Belgium and are a Facebook user, you might want to hold off on using Reactions.

The Belgian police force is warning its citizens not to use Facebook Reactions because doing so can threaten their privacy.

The country's federal police released a "Safe Browsing" advisory to the public on Wednesday afternoon that informs citizens that using the feature helps Facebook build a better profile about its users, with the information then being used for advertising.

"The icons help not only express your feelings, they also help Facebook assess the effectiveness of the ads on your profile," the police's website says.

The social network launched its new buttons back in February as a way to allow its users to better react to post as an alternative to clicking "like." Reactions include: love, haha, wow, sadness and anger.

While many people like the new way to interact with posts on Facebook, the Belgian police force does not want its citizens taking any part of it. By refraining from using the feature, the company will not be able to collect information about them. 

Facebook Reactions allows the company to know how its users feel, which can be useful for advertisers. For example, if a Facebook user appears to react positively to many posts at a particular time, the company would then be able to determine the user might be in a good mood and that this specific time is perfect for showing them particular ads. If they are feeling sad, they probably won't want to be bothered.

The Belgian police are aware of this and want the public to also be careful about how they engage — if they care about their privacy. It writes that the feature encourages users "to express your thoughts more easily so that the algorithms that run in the background are more effective."

This is true since Facebook has revealed when a user reacts to a post — even if they are "angry" about it — the algorithm detects that, since they are engaged with this content, it will continue to show more related content. 

All users concerned about their privacy should think twice before they click their next Reaction.

Source: Forbes