Write your own ‘blog’/‘wiki’/‘hypertext’.
Build interactive stories visually. Truly one of the best ways to teach an elementary-age child to write computer programs.
The most minimal and still very sweet way to participate in The Web. The child of watershed linksite Delicious, same conceit: post your bookmarks publicly, add a little note, a few tags. It’s like having your own href.cool! $11/year, but the real deal is $25/year and it’ll archive all the pages you link to.
The tilde.club was a 2014 resurgence of tilde-style user directories. You used to get these free at your university or with your home Internet connection in the '90s.
If you need to post something controversial or to subvert algorithms or bots for any reason, you can hide your text in these. (Hat tip, @foone.)
No, let’s not forget the TiddlyWiki. This is a personal wiki that you can edit and save on your own computer. If you need to put your wiki online, you can use TiddlySpot. A more polished but less powerful service can be found in Notion or notepin.co.