Apple has Siri. Amazon has Alexa. Now, Windows introduces you to Cortana. It is a Windows feature that allows you to talk to your device like how you would do with a person. Cortana can understand your conversational languange and she is able to respond to you in a human way as well.
Unlike other devices' virtual assistant, Cortana also works on PC's not just on mobile phones. It will also do more than just information retrieval. Microsoft designed it to do much more. It can handle your communication, calendars, and it has a better grip on giving you what you need.
Microsoft shares the journey of creating Cortana, saying that it presented them a unique challenge. They went through a series of questions that aimed to help them produce the perfect AI for their devices. They had to figure out how to create an algorithm for Cortana's human personality. It is also important to specify what personality should be given to her. Her intelligence and niceness are two other things that they also needed to be firm about.
This is why Microsoft conducted an interview to a number of assistants that worked for executives and CEOs, to find out what it takes to be an ideal assistant. What they got from the interview is the common fact that assistants need to have an extreme knowledge of their bosses. It's not as simple as knowing what's on their scheds and who they do not want to talk to. An assistant must also know whether his/her boss prefers vegetables over meat, 70's music over 90's music, etc.
Cortana was designed following the information obtained from that study. Microsoft developers wanted to give its users more than what any other AI can give them. They want a feature that does not only informs you of the flights that occur in different airports, they want a feature that will do the booking for you, get you an aisle seat, and reserve you your favorite meal.
Cortana has to know you to serve you. To do those things, Cortana will have to read through your email, see your sched, track the people you follow, and even see where you went last summer. It's like having an actual assistant-employer relationship where trust can be built over time.