I am deeply fond of keyboard-driven browser-based outliner Checkvist (see description and screenshot at https://checkvist.com/auth/help). It's similar to Workflowy, and quite featureful. Like Workflowy, you can "zoom in" to a branch and only view it and it's children, which is very helpful when editing complicated outlines.

It seems like a good product, but it doesn't fit my requirements because (1) it doesn't support plugins to specialize its functionality to particular domains and (2) its reliance on the mouse looks like it would make it far too inefficient for the kind of work I would like to do.

It's an interesting project, though, I'll try to check it out and see what I can learn from it.

Workflowy has keyboard shortcuts for pretty much everything. I've been using it for about 6 months now and I swear by it.

Workflowy is an enlighteningly simple app (it's really just bullet lists with zooming) but it's incredibly effective for what it does, and the free-form nature of it makes it easy to just brain-dump random notes to get your thoughts out into text. I use it to do rubber ducking [1], because just the act of putting my problem into text helps me organize my thoughts. I can't say enough good things about it.

[1] http://c2.com/cgi/wiki?RubberDucking

Not sure about plugins, but adding keyboard shortcuts shouldn't be hard, via a browser extension for example.

I use workflowy everyday and it's really cool; it doesn't feel very actively developed though, and that's a shame.

Also, try their search and hashtags: just brilliant!

you don't need a mouse, everything has keyboard shortcuts. hit ctrl-? for a list.

There aren't even any screenshots. I have to sign up to even see what the thing looks like..

so I have no idea.

Check out my app - https://zetabee.com/text/

There's a screenshot and a live demo. Workflowy is more advanced and capable. I made my app solely to note down everything. I have been using it for 4 solid years now and it has helped me organize my life.