Rated 5 out of 5 stars

Awsome idea! This should be integrated into CSS with a ":bookmark" pseudo-class ;)

This review is for a previous version of the add-on (1.5.1-signed.1-signed). 

Funny you mention that. This addon was a direct reaction to the sad fact that there is no such CSS pseudo class. It seems like a pretty natural idea.

Edit: I have just released a new version (1.7) that adds CSS classes to bookmark items.