Assegnate 3 su 5 stelle

This add-on doesn't work for me on Thunderbird 3.1.4 but I can confirm that Sighurts addon at:
https://nic-nac-project.org/~kaosmos/index-en.html
works fine - you do need to add it to the toolbar via "View > Toolbars > Customise".

Hasn't taken it upon itself to spam my address book yet... ...which makes me wonder why he's not added it officially to the add-ons site.

But it's very simple and works fine.