A lot of people are looking for a note taking application that merges a lifelong knowledge base with wiki-like linking features. There are many competing alternatives to consider, here are a few I've seriously considered.
name
WYSIWYG
backlinking
local
file-based?
self hostable
price
limitations
Roam Research
yes
yes [[link]]
no
no
no
TBD (~20/mo?)
everything is a bullet point
BoostNote
no
???
yes
no (on roadmap)
yes
free
???
PolarBookshelf
What I think most of these are mising is a connection between the context of where a though came from/was inspired by and the text/images/video that the user generated off that context. This is why I think Xanadu-like linking (see this demo) is one way a new competitor could differentiate themselves from the other knowledge bases.
A few notes on requirements (sourced primarily from Hacker News):
file-based, so that: migrated to other tools edited with robust classic text editors * copied, synched and backed-up with external file tools
This is essential so that persistence of the valuable knowledge stored in the application won't depend exclusively on its (fragile) internal tools, but can be managed as a system-level admin task.
Tree-based, but with external links, to allow for arbitrary network shapes (the basic "tree" outliner shape can be augmented with links to other parts of the network, without having to copy the whole sub-tree)
Multi-directional (incoming+outgoing) links (This is hard to see in most outliner note-taking tools, but Roam does it pretty well)
Easy navigation of parts of the tree through breadcrumbs (allows avoiding the "humongous tree of death" by creating "local navigation" views). Workflowy does this very well.
Tag-based persistent filters that can be stored as nodes in the tree (i.e. you don't need to search in the search bar for a combination of tags every time you want to recover it). With this, you can create new concepts by storing persistent complex searches as part of the tree.
Easy to set up, share, and use in multiple devices and OSs (mobile and desktop).