An attendee checks his mobile phone while standing next to a poster of a model wearing the Microsoft Corp HoloLens-augmented reality viewer at the Microsoft Developers Build Conference in San Francisco, the US, March 31, 2016. Microsoft Chief Executive Officer Satya Nadella said his company is committed to playing a key role in the emerging market for artificial intelligence-based chat software. During the event, Microsoft released a set of tools which allow developers to build their own bots. [Photo/Agencies]