This is good advice, but (as he notes halfway through the post) "plain text" comes in a lot of forms. I would also add that for life-long storage of "whatever"

This is good advice, but (as he notes halfway through the post) "plain text" comes in a lot of forms. I would also add that for life-long storage of "whatever" you do probably also need attachments. (I guess we could say “plain files”. And for those, more JPEG/PDF than .doc/.cwk (Hi mom! :) ) For a couple decades I used my IMAP mail server's "Drafts" mailbox as a kind of poor man's Notion|OneNote|Evernote|Blahblahnote. It supported plain text, and attachments. It was enough, and more importantly, not too much. Today, I do use things like Notion and other locked-in products, just to know the landscape (sure has gotten better since the 1990s! wow!), but if it is anything more important than a grocery list (such as, say... scraps of my novel, baby name lists, pet name lists, boat name lists...) I make sure to use something like Logseq, Marktext, Obsidian, or yeah, just .txt.