Zotero is an open-source bibliographic tool that makes it easy to pull bibliographic information about books, articles, and other media from the web and create bibliographies. Bibliographic entries can include pdfs of articles, and they can be annotated and tagged. It’s easy to create collaborative bibliographies by setting up Zotero groups; these can be private or public. Zotero would be useful for a class bibliographic project, or to serve as the basis for cooperative writing projects.
See the full library guide on Zotero.
Example:
DIgital History Reading Group
Further reading:
Pedagogy Toolkit: Zotero