Open and click-through rates (CTRs): Knowing who are engaged customers (those who open most emails and end up making purchases) versus inactive customers (who haven’t opened any emails in months) can be invaluable. Marketing campaigns announcing a new product should absolutely include those engaged customers, while re-engagement campaigns can be created to try and entice the inactive customers.
Use your real email signature: Just like using a real reply-to email address, you want to use real contact information within the email and the best way to do that is to include your contact details in the email signature. Giving your readers the opportunity to contact you or connect with you online is a great way to be personal and build a relationship with them.
When you're using email as a marketing tool, you're working on a pretty personal basis. This isn't ‘drive-by' stuff -you're directly targeting customers from their inboxes. There's a huge amount of potential which comes with this kind of marketing... but you'll only reap that potential if you REALLY understand both the marketplace you're operating from, and the audience you're talking to.