The developing world's favourite chat app is accused of spreading malicious rumours. In India the rumours led to the lynching of people falsely accused of child abduction, while in Uganda the government has introduced a controversial tax on social media platforms to stop alleged political gossip.

Ed Butler visits Kampala where he discovers how popular the app is, both for socialising and for business. Meanwhile Rahul Tandon reports from Kolkata on the unnervingly fast spread of the app across India. Plus Samantha Bradshaw of the Oxford Internet Institute explains what makes Whatsapp particularly well suited for lower income countries.

(Picture: Ugandan woman with painted nails using a cell phone; Credit: Godong/UIG via Getty Images)