So I see you can categorize papers, but can I tag them? Organizing my papers isn't a partitioning problem, its a tagging problem - a paper might be on several topics, and I want to get views of "e.g., all the papers on block-based languages".

I was wondering the same. It knows the concept of attributes, maybe you can define an attribute "tag"?

I like they compared it to Zotero, I love Zotero and it is perfect for keeping a personal, curated library for anything.