Rated 4 out of 5 stars

Nice add-on, really easy and useful.
Some suggestions for future development:
- Add an option to scroll the timeline from left to right (it's something more "natural" to me);
- Add links inside the "Visit Detail" window to other bubbles of the same site;
- Add an optional toolbar button.
One consideration: Horizontal position of bubbles in the timeline is determined by "time"; but what about vertical position? it looks like there isn't a criteria for it. Could it be "name" (alphabetical order)?
Keep it up!

This review is for a previous version of the add-on (0.5).