Cortana will be getting even smarter and more useful in an upcoming build which will bring some new user interface changes and more. In the upcoming build Cortana will offer much deeper integration with Windows apps than we have seen currently with Windows Phone. Some of the changes that were demonstrated were the ability to start a chat with someone with a simple "Hey Cortana, start a chat with Terry Myerson on Viber", and Cortana begins the chat.
Cortana can also surface new information for users. An example was when launching the Star Wars game, Cortana will tell you there is a newer, similar game that is out now. This will let you see new apps, without having to go hunting for them yourself.