For those who are learning about the app for the first time, ReachIt is an app that Lenovo showed off last May. It takes advantage of Cortana and basically gives it permission to go deeper into your files than it normally does. What this means is that you will be able to ask it to pull up files using natural language, as if you were speaking to an actual assistant and not a robot.
For example it will take into account your meetings, location, and who you met with (assuming you included that information to begin with). So users will be able to search for files and say, “Word file edited together with Robert last Sunday at Starbucks”, and it should be able to find and pull up that file for you.
Since ReachIt will be able to access online storage like Dropbox and OneDrive, you won’t be limited to just local storage. In any case you can get your hands on it by heading on over to the Windows Store.