Some useful tools for informal knowledge sharing:

Graasp allows people to map their personal and shared projects, interests, and activities into public or private contextual spaces integrating invited members, relevant resources and necessary apps which can be commented, tagged and rated.

Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share your research sources. That’s the tool to collectively build a bibliography about CROSS-FIELD relevant topics under the Zotero group “crossfield”.