Email newsletters were very popular about a decade ago when more and more people started to get emails on their mobile devices and therefore checked them often more than once a day. Over time marketing has evolved a lot and some companies question as to whether they should still do email newsletters.
When designing the newsletter, you should consider what it is exactly you want your newsletter to do. Is it to tell your customer about news form within your industry or business or is it to promote special offers or new products you are launching? You need to ensure that your newsletter is giving some value to your customers and one way to check this is by ensuring that you have data to check. You need to be able to see how many people have received your email (this will tell you how good your database is). You then need to know how many have opened it. This will help to establish if you are targeting the right people. Some systems will even tell you what links within the email they have clicked and what they did when they went through to your site. This data is vital in helping you make a decision as to whether it is worth keeping.