Why the Chinese video-sharing app seems to have Facebook worried. Plus, a leading AI researcher in Ghana tells us why algorithms used in Africa but trained on data from elsewhere could make biased decisions. And how a common definition of online abuse could help to tackle it more effectively. Presented by Rory Cellan-Jones, with BBC tech reporter Jane Wakefield, and special guest Parmy Olson, tech reporter from the Wall Street Journal. (Image: Stock photo of a woman on a beach making a smartphone video with her dog, Credit: iStock/ Getty Images Plus).