"If you use the open source Mozilla Thunderbird email
client, you're probably familiar with its powerful address book
features: import and export, online status information for your
friends, even synchronization. But one thing that's not so obvious
is how to do a mail merge to your address book contacts.
Fortunately, where there's a will — and some source code
— there is a way.
"Because Thunderbird is an email program, of course, if you
search for some variation of "mail merge" and "Thunderbird" you
will turn up a lot of hits for performing a mail-merge-like
activity with email: sending individual email messages to a list of
recipients, but with each one individually addressed, rather than
bulk-addressed in the To: or BCC: fields. Since this is a common
task and shares some of the same steps as performing a printed mail
merge, it is worth looking into briefly.
"There is a Thunderbird extension designed to do exactly this
email-merging task: Mail Merge, written by Alexander Bergmann. The
Mail Merge extension is compatible with the latest Thunderbird
3.0.* releases, and is cross-platform. It supports two features,
dubbed Mass Mail and Personal Mail."