No two outliners are alike, but there are certain common features frequently found in outliners:

• Basic Features - nesting, promotion and demotion, collapsing
• Styles - the ability to style text
• Multi-level Outlining - along with traditional outlines, the ability to attach text blobs to nodes
• File System Integration
• Folding - condensing a single paragraph onto one line
• Graphical Displays - representing the outline beyond a literal outline
• Embedding External Objects - moving beyond outlining text, sometimes including multi-media
• External Links - referring to the world outside the outline
• Internal Links - referring to other parts of the outline
• Cloning - One node in multiple places
• Advanced Node Manipulations - searching, sorting, selection by criteria
• Hoist - viewing a node as if it were the top of the document
• Columns - multiple attributes on a node, graphically displayed, sometimes with helpful tags
• Exporting - getting your data out in some other format
• Temporal Awareness - using your outliner for scheduling or some other temporal use
• Internal Scripting - the ability to script the outliner from the inside
• External Scripting - the ability to script the outliner from the outside
• Link Properties - attaching properties to links
• Instant Outlining - live updating of outlines as a collaboration tool

This list is based on ATPO Outliner Features 1 and ATPO Outliner Features 2,as are the initial writeups of all of the above, though it will divergewith time. Permission to use the content graciously granted by TedGoranson; we are particularly appreciative of the diverse set ofscreenshots he collected. Please leave this credit note.