CHATBOTS EXPLAINED: Why the world's most powerful tech companies think they're the biggest thing since the iPhone

Chatbots are the future, whether we're ready for them or not.

"It's technology that's inevitable," Microsoft's CEO Satya Nadella has said. On Tuesday, Facebook is expected to release a Bot Store in a launch that could define the next decade in the same way that the Apple App Store launch paved the path for companies like Uber to build a business off your phone.

So what are these chatbots, and why is everyone obsessed?