Yoono has been blocked for your protection.

Why was it blocked?
Starting with Firefox 34, current versions of the Yoono add-on cause all tabs to appear blank.
Who is affected?
All Firefox users who have this add-on installed. Users who wish to continue using it can enable the add-on in the Add-on Manager.
What does this mean?

The problematic add-on or plugin will be automatically disabled and no longer usable.

When Mozilla becomes aware of add-ons, plugins, or other third-party software that seriously compromises Firefox security, stability, or performance and meets certain criteria, the software may be blocked from general use. For more information, please read this support article.