A former employee of Google who worked on Google SketchUp program that was intended to create and to edit three-dimensional graphics quickly. Presently, this employee has been working with Valve on a new level editor for Portal 2.
The main feature is an incredible simplicity of the interface and the process of creating levels. Isometric icon graphics is the arrangement of objects by dragging and dropping from the library. All that let a large number of people to embody their ideas into a complete level, and in order to share that level, we do not have to go through the seven circles of hell with uploading files, because Valve are working on the browser of levels that is built into the game, which would allow uploading and downloading user's maps.
This news is taken from the book The Final Hours of Portal 2 that is written by Valve.