OmniOutliner is commercial outlining software

Outliner

An outliner is a computer program that allows text to be organized into discrete sections that are related in a tree structure or hierarchy. Text may be collapsed into a node, or expanded and edited....

 for Mac OS X

Mac OS X

Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

 produced by The Omni Group

The Omni Group

The Omni Group is a company that develops software for the Mac OS X platform. The Omni Group was informally founded as a NEXTSTEP consulting company in 1989 by Wil Shipley, who immediately brought on Ken Case and Tim Wood. The three incorporated together under the name Omni Development, Inc. in...

. OmniOutliner has most features of a conventional outliner, allowing the user to create nested lists of topics for almost any purpose, but has additional features extending its functionality beyond simple outlining. Recent versions of the software are universal binaries

Universal binary

A universal binary is, in Apple parlance, an executable file or application bundle that runs natively on either PowerPC or Intel-manufactured IA-32 or Intel 64-based Macintosh computers; it is an implementation of the concept more generally known as a fat binary.With the release of Mac OS X Snow...

. OmniOutliner received a Special Mention in the 2005 Apple Design Awards

Apple Design Awards

The Apple Design Awards is a special event hosted by Apple Inc. at its annual Worldwide Developers Conference. The event is meant to recognize the best and most innovative Macintosh and iOS software and hardware produced by independent developers, as well as the best and most creative uses of...

, and Macworld gave the "Professional" version its highest rating.

Outlining

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. The user can expand or collapse outline levels for easy viewing, sort topics, promote or demote the level of a topic, or "hoist" one level so only that topic is shown. It supports considerable control over styles, allowing the user to make global changes to the appearance of the outline at particular level. It also permits the user to add notes to any row, which can be displayed in-line, (i.e. within the structure of the outline) or in a separate pane below the outline. OmniOutliner documents can incorporate multimedia elements, including images, audio, and video, as well as PDF documents and web links.

In addition, OmniOutliner allows the addition of columns to the outline, so that the user can create rudimentary spreadsheets. 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

Microsoft Excel

Microsoft Excel is a proprietary commercial spreadsheet application written and distributed by Microsoft for Microsoft Windows and Mac OS X. It features calculation, graphing tools, pivot tables, and a macro programming language called Visual Basic for Applications...

.

Notably, OmniOutliner does not support cloning, a feature of some outliners that allows one topic to appear at more than one place in the outline. The Omni Group may, however, add this feature sometime in the future.

Extensibility

OmniOutliner supports scripting via AppleScript

AppleScript

AppleScript is a scripting language created by Apple Inc. and built into Macintosh operating systems since System 7. The term "AppleScript" may refer to the scripting system itself, or to particular scripts that are written in the AppleScript language....

, and users have extended the software to export to iCal

ICal

iCal is a personal calendar application made by Apple Inc. that runs on the Mac OS X operating system. iCal was the first calendar application for Mac OS X to offer support for multiple calendars and the ability to publish/subscribe calendars to WebDAV server....

, Apple's calendaring software, and even the iPod

IPod

iPod is a line of portable media players created and marketed by Apple Inc. The product line-up currently consists of the hard drive-based iPod Classic, the touchscreen iPod Touch, the compact iPod Nano, and the ultra-compact iPod Shuffle...

.

OmniOutliner was updated for compatibility with Spotlight

Spotlight (software)

Spotlight is a system-wide desktop search feature of Apple's Mac OS X operating system. Spotlight is a selection-based search system, which creates a virtual index of all items and files on the system. It is designed to allow the user to quickly locate a wide variety of items on the computer,...

, Apple's desktop search function introduced in Mac OS X v10.4

Mac OS X v10.4

Mac OS X v10.4 Tiger is the fifth major release of Mac OS X, Apple's desktop and server operating system for Macintosh computers. Tiger was released to the public on 29 April 2005 for US$129.95 as the successor to Mac OS X Panther , which had been released 18 months earlier...

 ("Tiger"). This allows content within OmniOutliner documents to appear within Spotlight's search results. The user can add metadata

Metadata

The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...

 to the document that Spotlight will index in its database.

Import/export

OmniOutliner's document format is proprietary, but it can export to OPML

OPML

OPML is an XML format for outlines...

, HTML, and several text and rich text formats. It can import from several other document formats (ACTA, MORE, Keynote, and Concurrence), as well as text and rich text formats.