Purchased lists are ineffective, and they impact everyone else who uses Mailchimp, too. If you send emails to a list of people whose contact info you bought, many of the emails will get identified as spam. Some spam filters will flag a campaign if anyone with the same IP has sent spam in the past. When you use Mailchimp, your email is delivered through our servers, so if one person sends spam, it could prevent other users’ emails from reaching inboxes. But by forbidding Mailchimp users from using purchased lists, we increase deliverability for everyone.
The success of daily deal email illustrates this. Customers gain value from a ‘daily deal' email and will come to anticipate the email in their inbox every morning. Tagging links in ‘daily deal’ emails will tell you a lot about the journeys within a given customer profile, as well as about preferences and behaviours. The ultimate sell is not important – what you are doing with ‘daily deal' (or ‘weekly tips') email content is building a relationship with your customers and learning more about how journeys within your brand work. All this information is important and can be put to use on later campaigns.
Edit. Even editors need editors. When you're working on your publishing calendar, leave plenty of time for the editing and revision process. Once you send a campaign, it goes straight to the inbox, and you can't go back and update it. Newsletters contain meaningful content, and sloppy ones reflect poorly on the companies who send them. Grammar and style are just as important for email as they are for websites and blogs.

Don’t talk down to people. I think this should be obvious. But looking at the email offers I get, clearly it isn’t. Don’t tell people, “Not buying this product would be idiotic!” or “Only a fool doesn’t understand the value in this service.” This whole email marketing strategy relies on you making people understand the value they can get from you. And sometimes that means making people see the downsides of not buying. But you can do that in a friendly, respectful way.

Address subscribers by name. Personalized emails are more successful. Buffer also suggests to personalize your emails based on need by sending emails that meet different user expectations. This makes them more targeted and more likely to be successful. Some studies show that educating and segmenting your audience will boost your click through rate on emails by up to 50%.
Personas provide a multi-dimensional method of targeting. They’re based, as the name suggests, on a projected persona for each customer ‘type’. Get it right, and personas can help you enormously in both predicting behaviour and personalising your communications. Personas are a powerful technique, and they’re increasingly used to improve the usability and customer centricity of communications.