YouTube Browser Bookmark Tagger от plasmatech8

Adds tagging buttons below the YouTube video player.

If the video exists in your browser bookmarks, then buttons will be displayed below the video player.

When you click on a tag button, the #tag will be appended to the title of your browser bookmark and the button will light up.

The tag is toggled on/off with subsequent clicks.

You can configure the tags available in the options page.