While this seems at least one way to share contents of a collection without duplicating it, I'm not completely sure if there are any caveats I'm currently not aware of.
Definitely not. So I got this wrong. Judging from the UX, I expected a different behaviour. It would be more intuitive if the key granted permission only to the the collection to the feed of which I want to subscribe. Thanks for clarifying!
+1, I´m trying to share a collection for a seminar, but not everyone is or wants to be in Zotero, and as much as I love Zotero it´s not adequate to proselytize in this seminar.
@manumanu -- this doesn't seem like the same request. If I understand you correctly, it seems like you're looking for a private sharing link, akin to what Dropbox or GDrive would give you. That's not an uncommon request, though I'm not aware of any work along those lines (it also raises some potentially tricky issues, legal and otherwise).
FWIW, people don't need to use Zotero to access a public Zotero group, so you could very much use that for a seminar, though you can't share files through that -- (in fact, making it impossible to share potentially copyrighted files through a simple link is one of the reasons Zotero would be reluctant to enable share links.)
Upgrade Storage
1) Select of of your collections, click on the three dots in the upper row and then choose "Subscribe to Feed.
2) You're now asked to generate a private key (choose an appropriate name and define permissions).
3) After clicking "Save key" the (atom) feed is downloaded
4) the first "id" element in the "top.atom" file is the URL of the feed (e.g. `http://zotero.org/users/0123456/collections/ABCABC18/items/top?direction=asc&sort=dateModified`to which you have to attach your private key by adding `&key=WHATEVERYOURKEYIS`
5) the key appears to be strangely hard to access. Go to the key overview page (https://www.zotero.org/settings/keys) and find the key behind the "edit key" or "delete key" links (e.g. `https://www.zotero.org/settings/keys/edit/WHATEVERYOURKEYIS`).
With the complete URL (e.g. `http://zotero.org/users/0123456/collections/ABCABC18/items/top?direction=asc&sort=dateModified&key=WHATEVERYOURKEYIS`) you can subscribe to any collection via your feed reader.
While this seems at least one way to share contents of a collection without duplicating it, I'm not completely sure if there are any caveats I'm currently not aware of.
FWIW, people don't need to use Zotero to access a public Zotero group, so you could very much use that for a seminar, though you can't share files through that -- (in fact, making it impossible to share potentially copyrighted files through a simple link is one of the reasons Zotero would be reluctant to enable share links.)