Just a heads up for anyone who receives a comment similar to the following:
After I originally left a comment I appear to
have clicked on the -Notify me when new comments are added- checkbox and now whenever a
comment is added I receive 4 emails with the same
comment. There has to be a way you can remove me from that service?
Your mailpress installation is very likely working fine, this comment is from a spammer / spambot. I did a Google exact match search for this comment, and it comes up with about 82,300 results, so they've been quite busy spamming this comment.