piatkow - 10:09 pm on Jan 6, 2013 (gmt 0)
Mail merge is standard on a number of email clients. SevenCubed's explanation of Thunderbird sounds more sophisiticated than the product I am using.
What you don't want to do is hit a single destination with too many emails at once. I used to have this problem with sending to AOL from a legit mailing list, all but the first couple of messages would be bounced.