Accessibility Privacy Matrix
A matrix of information accessibility (in terms of device sharing) and privacy (in terms of who can see the data).
Not accessible and private
This means you're just working on one computer. Any software will do here, though text file based software is better for portability. You can use Emacs or Obsidian here.
Accessible and private
You want to access your data on multiple devices, like a laptop and cell phone, but you don't want ther people to see it (for example, phone numbers).
This does not have to be web based, but CAN be, if it's a private account on a web application like Todoist or Roam Research.
But you can also use can use text files here, and something like Dropbox or Syncthing to share the files between devices.
Examples: my BBDB contact data, my TODO list, email.
Public
Public, in this case, means anyone can see it, and this implies accessibility - public and inaccesibility isn't really a thing. You want this if, for example, you want to give some of your data to your friends, like a recipe or a book review.
My blog is definitly public - it's meant for public consumption. That's the whole point.
You would also use this category if your data is nominally private, but if you actually don't mind it being public. This would describe my digital garden. The notes are "private" in that they are specific to me, but it's not like I mind people reading them and in some cases I want people to (like my recipes).
This can be just a website, even with data that is nominally "accessible and private". Org-roam, for example, should have a way of publishing the notes to a website.