Click here to read an article in the Huffington Post which does a great job discussing the merits of direct mail vs. e-mail.
Many of our own experiences with e-mail marketing were backed up by the data in this article.
Only approximately 20% of postal addresses can be matched with e-mail addresses, so if you rely on e-mail exclusively, you're not reaching 80% of the market. Those messages that get by the spam filters are quickly forgotten or lost amid new messages. If seniors are in your target market, you're in trouble as only approximately 45% of seniors are online.
Check out the entire article
here for more insights.