Because Zotero is open source and freely available to everyone, you do not have to use your Emory email address. You will need to register to sync your desktop application with the web as well as to create shared group libraries.
Sync to the Web
Go to Preferences to set up the sync function to use Zotero on multiple computers, to share references with groups, and to backup your library to the Zotero server.
For Macs the Preferences are located under the Zotero tab. On Windows, it's under Edit.
Enter the same Username and Password you registered with on Zotero.org.
To enable the Find it @ Emory function to collect PDFs in Zotero, copy and paste the blue URL below to the "Advanced" tab of the Preferences box, in the Resolver field.