Importing From Other Applications
In addition to its own documents, OmniOutliner can open (or import) documents created in other similar applications.
To open a document while running OmniOutliner, choose Open (⌘O) from the File menu.
(There are several other ways of opening a document which are generic to all Mac OS X applications; see Mac Help for more information.)

OmniOutliner can open documents of the following types:
MORE text files (.txt) - MORE is a popular outliner that has been around for a very long time. It can save files as plain text, and OmniOutliner can load these files, with some limitations. The rows cannot be numbered, otherwise the number is just treated as part of the text. Since this is a text file, you lose any font or color information from the original document. Importing MORE files works best when your rows don't have labels.
MORE files (.more) - These are MORE's native format. OmniOutliner can load these with some success, but it hasn't been extensively tested. Even with a simple document the imported text isn't quite correct.
Text files (.txt) - Regular text files. Each row begins with zero or more tabs to indicate the level, and tabs between columns. Columns are created as necessary.
iTunes song playlist files (.export) - iTunes can export song lists in a tab delimitted format. OmniOutliner can load these files, and takes the column titles from the first row. Large playlists can cause window and column resizing to be slow.
Concurrence (.concur) - An application similar to OmniOutliner for NeXTSTEP and OPENSTEP. It was a presentation program that had multiple views onto an outline and a slide editor. OmniOutliner can load the outline from a saved concurrence file, but not more than one of the views, the slides, or features like cloned rows that OmniOutliner doesn't support. This hasn't been thoroughly tested, and I don't think the import has been updated since we've added level styles, so Concurrence's level styles probably aren't imported.

It can also load files that are interesting to developers:
Property lists (.plist) - OmniOutliner creates an outline with two columns, key and value.
Strings files (.strings) - These are just property lists, so you can view them like property lists.
Sample files (.sample) - These are the files generated by the sample command line tool. You need to rename the files because the sample command saves them as a .sample.txt file. OmniOutliner creates an outline with two columns, one for the stack and the other for the sample count.

Why would you use this instead of the Sampler appplication? The Sampler application can't save the information it collects, so you can use the command line tool and look at the result later, or someone could send you a sample file to view. Or you could be sampling an application that takes over the entire screen, such as a full-screen OpenGL program.

The files that the sample command creates can be large so you may notice that OmniOutliner is slow. Resizing the window or columns can be sluggish. In this case you can collapse all, resize the window and columns, and then expand all. Very deep call trees may require a very wide outline column. you may want to select a row partway down the stack and then hoist it so that only its children are visible.
Related Topics
Table Of Contents: Advanced Topics
Exporting From OmniOutliner