Xememex is a multiuser TiddlyWiki from Federatial. It allows large groups of people to work together on intertwingled wikis that can share content. It is implemented as a serverless application on Amazon Web Services.
The largest customer implementation has hundreds of online wikis with thousands of users. See https://manuals.annafreud.org/
Xememex is currently only available under commercial terms from Federatial. Contact Jeremy Ruston at Federatial for more details.