MailChimp (a very popular email marketing service) has just released a study of interest to anyone who uses email for marketing purposes. We know that many of our clients take advantage of the powerful marketing features in FloristWare and routinely email their customers and we thought they might find this helpful.
MailChimp sends a lot of email (about 50 million a day according to their website) and they looked at the statistics for over one billion emails to come up with some answers. There is some very useful information in the report and, in addition to the "when" they also talk about the links you include in your email. Specifically the suggest that the more links an email includes the more likely you are to get clicked - suggesting that there may be a benefit to including links more than once.
You can see the entire report in the MailChimp knowledge base.