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.
This ties into the second 40 of the 40/40/20 rule – now you’re probably beginning to see why that was listed up front and why it’s universally considered the gold standard when it comes to direct mail marketing guidelines. With other forms of advertisements or marketing, it is perfectly acceptable to only go after impressions – a billboard in a highly-trafficked area or a TV spot that is more of a teaser in nature can sometimes go a long way toward educating the public of your existence, which is the first step in getting them to engage. With direct mailings however, you might as well be printing cash to send out to people if you don’t have a compelling call to action to give people.
In order to engage customers, retailers must shift from a linear marketing approach of one-way communication to a value exchange model of mutual dialogue and benefit-sharing between provider and consumer.[21] Exchanges are more non-linear, free flowing, and both one-to-many or one-on-one.[5] The spread of information and awareness can occur across numerous channels, such as the blogosphere, YouTube, Facebook, Instagram, Snapchat, Pinterest, and a variety of other platforms. Online communities and social networks allow individuals to easily create content and publicly publish their opinions, experiences, and thoughts and feelings about many topics and products, hyper-accelerating the diffusion of information.[22]
Project conversion metrics. The general rule of thumb is that the smaller and more targeted your list, the more you can spend per piece. It’s better to make a strong impression to a few than to make a weak impression to many. Know your cost per unit, and project a conversion rate, so you can estimate whether your campaign will have a positive ROI before running it.

Many consumers have reservations about online behavioral targeting. By tracking users' online activities, advertisers are able to understand consumers quite well. Advertisers often use technology, such as web bugs and respawning cookies, to maximizing their abilities to track consumers.[60]:60[95] According to a 2011 survey conducted by Harris Interactive, over half of Internet users had a negative impression of online behavioral advertising, and forty percent feared that their personally-identifiable information had been shared with advertisers without their consent.[96][97] Consumers can be especially troubled by advertisers targeting them based on sensitive information, such as financial or health status.[95] Furthermore, some advertisers attach the MAC address of users' devices to their 'demographic profiles' so they can be retargeted (regardless of the accuracy of the profile) even if the user clears their cookies and browsing history.[citation needed]
Emails triggered by milestones, like anniversaries and birthdays, are fun to get -- who doesn't like to celebrate a special occasion? The beauty of anniversary emails, in particular, is that they don't require subscribers to input any extra data, and they can work for a variety of senders. Plus, the timeframe can be modified based on the business model.

However, there is some juice when you buy emails list. If you buy 100,000emails and 85,000 happens to bounce it means you have a conversion rate of 15%. This is quite significant and why should I not buy if 15,000 are going to be good? How long does it take to have 15,000 people subscribe to ones list? If one is able to maintain and convert this 15,000 to become part of a sign up list, then can we not see that buying email lists could be a gold mine?

Publishers can offer advertisers the ability to reach customizable and narrow market segments for targeted advertising. Online advertising may use geo-targeting to display relevant advertisements to the user's geography. Advertisers can customize each individual ad to a particular user based on the user's previous preferences.[27] Advertisers can also track whether a visitor has already seen a particular ad in order to reduce unwanted repetitious exposures and provide adequate time gaps between exposures.[72]