Netvibes Premium for Teams uses a distributed architecture. This means that the Publisher creates and updates the master Dashboard and users start with a copy of it that they can customize to their liking. Library tabs are a special type of tab available to publishers on the master dashboard. Tabs of this type are are hidden from the user's version of the dashboard.
Library tabs offer a number of benefits. Content that the user doesn't need to see is hidden from them so they are not overwhelmed with too many sources. The sources remain available for analytics that are on the users' dashboards. Unlike ordinary and locked tabs, retention of sources in library tabs is synced between master and copy so that analytics apps created with the same query will match on each version of the dashboard.
To set a tab to be a library, open the tab options and check the "Library tab" option:
The tab can then be identified as a library tab by the book icon.
An automotive manufacturer has a Dashboard on electric cars. The Publisher can include all renewable energy sources for the user to read and have all the national newspapers and magazines as hidden “libraries”. This way, if something important was to happen in the mainstream press, Analytics would report it on a daily basis, but users don't have to read every article from every feed in their real-time news stream.