Personal assistant bots like Siri and Cortana have a serious problem

Assistants are all the rage right now. Everyone seems to be working on one. People imagine them becoming the new interface to computers -- why bother with apps and searching the web when you can just ask your assistant to do it for you? Yet, a major challenge stands between the dream assistant and the current reality. It's called the multi-agent problem, and most companies are reluctant to talk about it.