App Space is an organizing concept designed for keeping app-specific entities separated from other apps.

Strange, but Document is a Media, actually.

Link represents a link to a given entity, placed in the same or a different Model.

List is a fundamental organizing and grouping concept in Zet Universe. List represents a 1D group of things where order of things is not explicitely defined.

This is the class of motion pictures created by recording using cameras or by creating images using animation or other special techniques.

The class of artifacts that are closely related to music. Musical artifacts include compositions themselves and related artifacts such as cover art on albums, written scores, lyrics, and other things.

This is the class of musical playlists that may be created by Zet Universe users. A Playlist is composed of a number of musical works. A Playlist is a kind of List.

Generic list of people organized into a group.

(Project) Space is a fundamental organizing and grouping concept in Zet Universe. It contains individual entities grouped into visual clusters, or into lists. Every single entity always belongs to one or more visual clusters.

Recorded TVs are a special kind of entities that represent TVs recorded using Windows Media Center. Recorded TV is a kind of Video.

Movies, television programs, YouTube videos, and any other recorded "moving picture" is classified as a video.

Visual Cluster is a fundamental organizing and grouping concept in Zet Universe. Visual Cluster represents a 2D group of things where relative location of things is explicitely defined by user or automatic layout algorithm.

Web Page is a Media

Zet Universe is the name of the information organization, tracking, analysis, and retrieval system.