How I Use OmniFocus Notes
I use OmniFocus to keep track of what needs to be done on an individual level. All sorts of projects, from buying and framing art to starting hobbies to making notes about things to look up later get jotted down in OF. If I was ever lacking in things to do, that is no longer the case, with almost 900 open actions in 117 projects. (Not included: routine tasks that a checklist is a better fit for.) OF does not track tasks that work expects me to do, since in that case I'm accountable to others, and priority set not necessarily by me. In tickets, I always try to log what I did at the time of doing it, so that others can piece together later what happened.
So I do the same in OF notes for a task. If it's a repeating task, I write down if anything had changed since the last time and whether there were roadblocks I came across so that when I do it the next time, I can avoid them. For tasks waiting on something to happen (a delivery, for example), I make a note of the updates that come my way. Every entry in the notes gets a date associated with it, just in case I need to look up when I did something that has to do with that task.
I try not to put notes from a call or meeting in OF, since they end up being harder to find. I settled (finally) on the iOS/Mac Notes app, which syncs across all the devices I use at the moment. Whenever possible, I add a link in the OF note to something that's referenceable by URL. A Day One journal entry would be a good example, or a web page that came in handy when looking into something.
I wish there was Markdown in OF notes, but there is quite a bit possible with formatting without it, so it would only solve the problem of making bullet lists easier. (I have a text expansion shortcut for the bullet • for when typing a bullet list out on a Mac.) Sometimes OF notes become blog posts, like a forthcoming one on a synthesizer purchase, on its way from who-knows-where, the outcome of which I'm still not sure of. Usually, though, it's a way for me to track what I did and when over the lifetime of a task, and to be able to bring up a timeline if need be.