Rated 3 out of 5 stars

by R on Dec. 5, 2012 ·

There is a bug: The extension seems not to see contacts that have been added to a mailing list in the adress book window. It then removes them from Google Contacts. I had to delete the mailing lists, to get working sync again

by Leni Mayo (Developer) on Dec. 12, 2012 ·

The addon doesn't support thunderbird mailing lists.
It supports google groups instead.

See:
http://zindus.com/i/mailing-lists
http://zindus.com/i/contact-wont-sync