As mentioned earlier, technology and the internet allows for 24 hours a day, 7 days a week service for customers as well as enabling them to shop online at any hour of that day or night, not just when the shops are over and across the whole world. This is a huge advantage for retailers to use it and direct customers from the store to its online store. It has also opened up an opportunity for companies to only be online based rather than having an outlet or store due to the popularity and capabilities of digital marketing.
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.
Most of the article really talks about how to successfully get an email of a person who has already landed on your landing page/podcast page/affiliate/blog etc. but how to get those people there in the first place is a bigger challenge. Also, one of the ways you can include in your list is by offering free tools/widgets. For example, OpenSiteExplorer by Moz is a great example. Evergreen and very useful for the target audience.