I'd like to suggest a place to create a reading queue or to-do list. This would be similar to the 'related items' tag, but geared towards creating an orderly list of works to be reviewed. Since Zotero makes it so easy to collect items, sometimes I find that I forget what I've collected. And, while I read a source, if it cites something I want to read later, I can certainly get the citation into Zotero, but many times I forget to read that new item later. A 'reading queue' would be a place to collect items I intend to review - kind of like a playlist in iTunes.