Includes Search, Advanced Search, and Zotero Reports. You can also join Zotero Groups (public and private groups have different levels of materials), and capture data from individual's public Zotero libraries.

Visualize your Zotero library data using word clouds and other visualization/clustering techniques. Also works with Group Libraries (but what is extracted depends on level of access)

Note the category for Library Analysis/Visualization via Voyant

Requires a little work, but the post includes step-by-step instructions.

Note: "...For readers wondering if Paper Machines is right for their needs, the Library at Emory has conducted an excellent comparative case study of Paper Machines, Voyant, MALLET, and Viewshare. That succinct comparison showcases the strengths and weaknesses of each project..."

While this is not specifically about Zotero's instance of the MALLET topic modelling tool, it will help you learn how to use it.

does not seem to need an account, but probably works best with one.

A really nice social bookmarking site (my personal favorite - check out my library at https://www.diigo.com/user/loenglish )

social bookmarking site - the grandmother of them all...

A different way to search Google Scholar for people or journals