Every time a link is published to another wiki, the linked wiki looks at the referrer, and if it passes the acceptance criteria (e.g. its domain is on the whitelist and it is well-formatted) creates a backlink.

I wrote more about this in April 2022, explaining what I am talking about in more detail.

Essential and central to this concept – Roam Research does this only within each separate implementation (as far as I know) – or as happens with some blog systems. This would make linking feasible and maintainable across domains, effectively making traversing wikis easy across multiple hosts.

Ordinary backlinking within a wiki instance is done fine in existing wikis. What we're talking about here is cross-domain or cross-instance backlinking.

In outline:

• either: the linking page sends a special kind of message to the linked page when the link is created,
• or: the linked page looks at every referrer
• and in both cases the linked page is acceptable – if so, it links automatically
• the user could specify rules about classifying incoming links
• alternatively, incoming links could be put on a list awaiting manual sorting and approval
• or some combination

Optionally, a link checker could be run every so often and delete or alert the owners to dead links. Ideally, some alert, or visual cue, would enable editors (and possibly readers) to see when a referred-to page has changed.

It might be possible to delegate some of the work to a SaaS API, but I doubt that would be useful given that it should be a relatively simple process to identify the referrer from the header and then insert an automatically formatted back-link. This might require only the addition of a few lines of code to one or two functions in the wiki engine. It might be possible to create a simple plugin to overload the functions affected.

Fedwiki has automatic backlinks.

MediaWiki has two apparently unrelated mechanisms (though only within one wiki) and I see no need for them to be separate:

1. What links here
2. Categories

Some kind of update checking would be useful, so that any reader knows whether a linked page has been changed since the last revision / update of the currently viewed page. More below.

MassiveWiki will do this later…