What does it mean to sync data with my Zotero account? Why should I?
Syncing data with your Zotero account links the data (citations, notes, tags) that you save using your browser plugin with your online Zotero account. When you sync data and files to your online account, this information becomes accessible to you from anywhere and allows you to share those citations with others. Data syncing is free and has no storage limit.
Once you have registered for a personal account, you can then adjust your preferences to sync data (and files, if desired) automatically. Simply open your preferences panel (from your Zotero window) and select "Sync automatically."
You may also sync data manually by clicking on the green refresh button above the third pane (in your Zotero window)"
In addition to syncing your citations and other data, you can also sync any associated files in order to retrieve them remotely. These files might include PDFs, screen cpatures, or images. Unlike Zotero's data storage, free file storage is limited to 300MB of storage space. However, users may purchase additional storage space at a tiered rate for storage capacities larger than 300MB. See https://www.zotero.org/support/storage for more information.
To sync files with your Zotero account, check the appropriate boxes (for individual and group accounts) from the preferences screen (shown above).