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: "...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..."