Emacs org-mode is very powerful tool for personal knowledge management, but can be hard to learn, makes it hard to have the same content (notes) referenced in more than one place, and can be awkward for the hands.
Finding other tools inadequate for various reasons, I wrote OneModel to meet my own needs, and made it available. If you touch-type, it is extremely fast for to-do lists and notes of all kinds, and I generate the project web site from part of its data. It is much easier to learn and faster to navigate than emacs, and you can have the same content in as many places as desired, without duplication.
But it wants to be more: It uses an internal structure that has big future ideas for knowledge management, like embedding code within groups of entities, or linking across OneModel instances, so you can choose to share data from your personal organizer, or subscribe to (or copy) data from other instances: like a wikipedia but where the internal knowledge is structured so can be used for computation, rich queries etc. Imagine asking a system: what villages in history had economic improvements in a 4-year period, all external conditions being equal, and what do those cases all have in common?--that is the long-term vision of the system. The vision and internal structure are intended as be a prototype of a platform to manage all mankind's knowledge as a usefully computable whole.
The web site has a few screen shots (remember it's an ugly prototype but works well! -- I have my calendar/life notes/todos/contacts etc in it now) and a demo system to play with without installing anything.
(It is written in scala, using a simple/approachable coding style that should be readable by most programmers with just minutes of scala knowledge--I hope--and uses postgresql for the data.)
I frankly don't mind if someone else takes the ideas and does a better job with them: we can do better than managing mankind's knowledge in the form of huge sophisticated piles of words: words are not the real knowledge but a superstrate over it, and they are hard to compute well. Feedback welcome.
Thanks for the question. Maybe I'm starting to see better why people think it's hard.
The thing with OM is:1) everything is on the screen, and reading it should be all you need to do at any given time. There are only 10 things options didn't create yourself at any given time, and only about 2-4 you'd use often. 1 2 and 4 being the main ones. That's why I haven't made a "user manual" (yet anyway)--there isn't much to tell that one can't get by reading the screen and trying it (or so i have hoped). And,2) everything else on the menu is something that was created and put there by the user, you, and arranged by you, and those get letters or other characters assigned dynamically. So if you create one entity, it is 'a', and you type a to go to it and do more with it. If you create a 2nd entity (sibling to a), it is b unless you reorder them with menu option 2. Next being 'c', and so on. If you create something new under 'a', it is 'a' when you are inside the first one. They are yours and you can make them however you want which is in effect making the keystrokes familiar. Sometimes I get mnemonics out of that ordering: I have one set of things (shown on the OM site also under getting started), one of my top menus or groupings I use , where I can remember what to type because mentally I associate them with letters of the alphabet and in that particular case it's handy. In other places I just get used to what I have put as 'a', 'b', 'c', 'd' etc.
It is really easy to use I think, once you do it for a little while.
Then maybe you can tell me what I need to say to new users to make the first couple of steps easier! :)