Hi there
I'd like to announce PanoTag, our plugin for Facebook tagging: https://krpano.com/plugins/userplugins/panotag/#top
The plugin is freely available for download and the tagging system is running on our servers. This means that there's no need to install or configure anything on the server side. Just download the plugin, configure it and you're ready to go. A free version allows you to have up to 10 tags per panorama, so feel free to try it out.
This is the first release, so please let us know of any bugs you find here on the forum. Also, some features are still under development, most notably a better caching system for when the server is under heavy load.
Hope you enjoy it!