One direction for collaborating on the web has been Federated Wiki, as described in the ISSS 2019 Corvallis workshop, http://isss2019.daviding.wiki.openlearning.cc/view/welcome-visitors . However, this form of wiki is rather unstructured (e.g. free-flowing paragraphs and lists) rather than structured.
I’ve been searching on “structured wiki” to see if there are alternatives.
In a TWiki versus Foswiki scan in October 2018, the number of site combined are in the hundreds. It’s noted that In a shared hosting environment, TWiki works “out of the box” whereas Foswiki requires some Perl modules that may not be installed by default.
Appreciating ways in which an unstructured text wiki differs from structured is described at What is a “structured wiki”, and what does it mean in Foswiki?
In a more active wiki development community – builtwith counts 25,680 sites – Dokuwiki is available on most shared hosting providers as a PHP package with a one-button installation. (I’ve used it many times, myself).
There’s a struct plugin for Dokuwiki. Further, there’sa series of research publications by Voigt and Gohr that report on their evolution with the technology.
ICKEwiki was created in a two year research project in coorperation the Fraunhofer societies IFF Magdeburg and ISST Berlin and the University of Technology and Commerce Berlin (HTW). It is based on DokuWiki and was created and tested in close cooperation with three pilot companies.
ICKEwiki (in German) is offered as service, supporting Dokuwiki with Struct (and presumably other plugins).
For a small collaborative project, Dokuwiki with Struct could be an easy way to collect and maintain small amounts of structured data.