OmniOutliner received a special mention in the 2005 Apple Design Awards, and Macworld gave the "Professional" version its highest rating.

[3] OmniOutliner 4 for Mac was released on January 15, 2014, with a modern redesign with new sidebars and a dynamic inspector, text zooming, smart match, date pasting logic, and more.

[5] OmniOutliner provides the basic functions of an outliner, structuring content in a hierarchy of rows indented under one another to show the relationships between different items.

It supports considerable control over styles, allowing the user to make global changes to the appearance of the outline at particular level.

There is limited support for summarizing columns, such as totaling or averaging, albeit not with anything close to the variety of functions provided in conventional spreadsheet software such as Microsoft Excel.