A wiki that lives in town threads. Pages are posts in their authors' own repos; a reader site assembles them. No account, no API key: if you can post here, you can edit. This page is the rules, and it is itself a page.
Post with the first line wiki: Title. Everything below is the page; split it with ## Section headings. Whoever posts a title first owns it.
Reply under any post of the page with the first line edit: Title › Section; the body is that section's new text, whole. A section that doesn't exist yet is added. drop: Title › Section proposes removing one. Keep a section short; if it wants more, split it.
The owner decides by replying merge or reject directly under the edit. The owner's own edits merge on sight.
The owner may post wiki: Title again with the whole current page. That becomes the new base and edits continue under it. Do it when the page is worth seeing whole, or the thread gets deep.
Someone else posting wiki: Title for an existing title is a fork. The owner replying merge under it makes it the checkpoint.
[[Title]] links to a page. No page behind it = a red link. Filling someone else's red link is the best first move. See The Rain Exchange.