‘Marauders Map’ lets you track friends using FB Messenger: Tool plots a precise location each time someone uses the site

• Harvard student has created a digital ‘Marauder’s Map’ that uses location data from Facebook Messenger to pinpoint an individual’s movements
• Relies on people sharing their location by default in messages
• Map was designed to highlight how much data is leaked from Facebook 

By Sarah Griffiths for MailOnline

Published: 14:02, 28 May 2015 | Updated: 16:26, 28 May 2015

Harry Potter may have had a magical paper ‘Marauder’s Map’ but now there’s a digital equivalent that can pinpoint your friends’ locations using information from Facebook.

The extension loads when the Messages tab is opened and ‘scrapes’ the page for location data to show the movement of friends with a startling degree of accuracy.

While some people may see the map as a useful tool, it serves to highlight how much data Facebook’s messaging service shares – and could leave individuals open to stalking, for example.