Things I want from an outliner:

• Expand/collapse branches of the tree (a.k.a. “folding”)
• Brain-dead easy to use
• Works on Mac, Windows. Nice but not necessary to work on Linux or in a web browser.
• OPML support

Candidates:

• Atom editor with FoldingText extension
• Sublime Text with plain text
• My Life Organized
• LooseStitch
• Sproutliner
• iOutliner
• Bonsai

Issues and observations:

• Atom + FoldingText extension
  • This is interesting. Works on Windows, Mac, Linux. Can view documents with Google Chrome; could view on Android/iOS via DropBox and Chrome.
  • Non-intuitive for infrequent users. Steep learning curve. Keyboard driven and you’ll need a cheat sheet if you haven’t used it recently.
  • It is not open source, but the source is available in Python. If it gets abandoned, you could probably keep it going.
  • Some key bindings are a little funky on Windows because he doesn’t use Windows himself.
  • I’m going to try making this my Outliner.
• Sublime Text with plain, indented text.
  • Crude. You just enter your outline in plain text. Tab to indent. Sublime Text gives you folding for indented sections, as if it were code.
• My Life Organized
  • Windows only. It is focused on GTD. Desktop application. Synchronizes tasks with Outlook. Does not do OPML well
  • Retarded about Alt-F (press and release Alt, press and release F)
• LooseStitch
  • Web based
  • Can’t list all my outlines in the free version (can in the $25 per year version)
• Sproutliner
  • Web based. Abandoned. Withdrawn.
• iOutliner
  • Web based
  • I can’t find a way to delete an outline. (4/20/2009).
  • Slow
• Bonsai
  • Windows only. Feature-complete, general-purpose outliner. OPML support.
• The Fargo family: (No organization of outlines - File/Open shows one long list.)
  • Fargo - discontinued in 2017; like LittleOutliner, but stores in DropBox
  • LittleOutliner.com - basic OPML editing. Stores on his server, but you can export OPML and may be able to set up your own server via http://my.1999.io/users/littleoutliner/2016/07/06/0003.html and RTFM at http://fargo.io/docs/outlinerHowto.html
• Oak - only stores in browser’s local storage
• Concord - GPL, Javascript, browser local storage; http://scripting.com/2013/09/16/concordOurGplOutliner
• OmniOutliner - great; huge; only Mac and IOS
• OneNote - No export to OPML; I’m familiar with it. Works on Mac but not Linux. Can paste in images (but they take up a full line). OneDrive but local cache. What do I do if MS drops Mac support?
• Evernote - doesn’t fold
• Cloud Outliner 2 $9 - simple; Mac and IOS only

For all the web-based outliners, I’d need a daily export in order to protect myself if they summarily shut down their web site. For desktop applications, I’d just need to add the data files to my existing backup process. Web-based outliners come closest to running on Linux/Windows/OSX/iPhone/Android, assuming I use the web interface from the cell phone.

I work for a company with pretty restrictive web filtering. At the moment, I can get to the online outliners, but there is always the risk of being cut off. For the web outliners that are open source, I could always install them on my server, but that is geekier than I want to go for an outliner. Of course, if it isn’t web, at the moment, I can’t get to it when I’m away from my desk.

Observations:

• I’d like to store data locally so Spotlight can find it. But I’d like to store it in the cloud, so I can use it from multiple clients.
• As an outliner, I really like Bonsai, but I can’t get past the Windows-only. I’m not going to run it in a VM.
• OPML is a big deal, because it lets me exchange data with other outliners. You can export from MLO, but it takes some massaging to get the data into another outliner.
• If I had a Mac at work I might use OmniOutliner Pro.
• MLO works well for GTD, but Bonsai is a better general-purpose outline (IMHO).
  • MLO will synch with Outlook tasks. This is helpful because I can drag an email to my Tasks folder, and add a to-do with the email body as reference.