Over the years I've searched for, tried, stopped using, used again, reconsidered, stopped using, considered some more on note-taking/recording/filing systems.
Generally I've opted for computer-based systems but have also tried paper-based methods.
The list is probably not complete, and in no particular order:
I would class Treepad, Zim and Cherrytree together in the same forest; to do lists and bullet journals in the same paddock; notebooks (including DIY Planner) as the medium rather than the method; and my brain as the fallback for all of the others.
I like the idea of the simplicity of paper-based systems, but the falldown for me is that I don't want to carry it around. I like the idea of computer-based programs, but that means having the application available on all machines, and/or internet access.
I've also pondered the idea of a wiki - some computer-based system that allows for thoughts/plans/facts to be stored and retrieved. I've resurrected some of these thoughts recently and had another look at personal wikis. A couple of the standout ones were:
I'm in the process of setting up my TiddlyWiki. It resides in Dropbox so is accessible from any computer I regularly use. So far all seems fine.
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