"Reading queue"
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.
You could also use tags.
Arbitrary ordering is a separate feature request that's been discussed previously and may happen eventually.
Unfortunately, my real work is 98% pdf's (true for most people in science, I think), which, since I rely heavily on annotations, I don't read in a browser... so tagging the page in the browser, then following that back to the zotoro entry (which I don't know how to do automatically?), then clicking "show file", then opening it in acrobat, then remembering when I'm done to go back to the browser version (which has to be still open) to take it out of the queue isn't any faster than just keeping a typed up, hand maintained list in a document, really....
Thanks for the suggestion, though!