If you are working on a project with others, or if you need to share your reference library with a group, Zotero allows you to create shared Group Libraries.
To create a Group Library, go to the Zotero website, log in, and click the "Groups" tab. Then click "Create a New Group." Give your group a name and select the membership type. After your group is created, it will show up as another library within your Zotero application. You can invite people to the group and even share PDFs depending on the membership type.
Sharing Your Library
If you need to share your library with others, such as for a conference presentation, all you need to do is share the URL of your library when accessed via the Zotero website. Each folder in your library has its own URL, as well as RSS feed.