Review for Duplicate Contact Manager by auser
Rated 2 out of 5 stars
Should be noted that over 1000 contacts and this extension may do wonky things which the author even mentions, but not on the opening page. Had I known that, I wouldn't have downloaded it. It does appear it does what it claims, just not for people with massive address books. Please make that clear on the download page.
This review is for a previous version of the add-on (0.3).To create your own collections, you must have a Mozilla Add-ons account.