I don't know why I haven't mentioned this app before. It is an outlining app that is really very good. I’ve been using it as both a browser-based web app and an iOS device App. The web app is CarbonFin’s Outliner Online. An account is free and can be used as a standalone web app. One of the nice features is being able to share outlines with others for collaboration; or you can publish the outline so that it can be viewed by browser by anyone with the URL. Even a tablet browser works pretty well with the Outliner Online to give you mobile access.
However, if you are on the iOS platform, the $5 universal App is actually a much better experience than the web app on a computer. Even on an iPhone.
Some of the features of iOS App, Outliner by CarbonFin:
The pictures below show some of the options. The picture on the left shows me using Outliner to keep a checklist of management tasks that I was working on.
The ability to add a note to the item could be used to capture instructions, background, examples, or descriptions - any text you like. And, of course, Outliner can be used for anything that lends itself to a outline format. Some ways I’ve used Outliner: