There was a debate in past years as to whether to send out newsletters in text or graphical html format. Some people insisted that you should send out newsletters in text format, because a lot of people and companies have programs set up on their computers to block graphics for fear of viruses. Others believed that graphical newsletters look more professional, gave a consistent look with their other marketing materials, and that people are more sophisticated about whitelisting so the spam filters don't block your publication.
A lot of people thought the best solution was to give your subscribers a choice as to whether they would rather receive your newsletter in text or html graphic format. Programs like phplist can be configured to ask this. The downside is that you have to create two different versions of your newsletter.
With modern browsers and better protections, most companies send out their newsletters in html format today including a lot of graphics and some even have videos embedded into them. To get around software programs that will not display it properly, there is code injected into the newsletter that gives a link to the online versions for them to read.
Listing Partial Articles
There is another format option that you need to take into consideration. You can include the entire article in the newsletter or include a partial article with a link to the full article at your website. Most major publishers have gone to the partial article format, because this keeps the content where it belongs, working for your website. By routing your subscribers to your website, they will notice any updates and/or special offers that you may have.
In addition, people often get multiple newsletters each week in their mailbox. Not every article is applicable to every person, so it is convenient for most people to just scan a summary of the articles and click on a link for more information. There is a greater chance of them scanning your newsletter in this format, than if they have to take the time to read through the entire newsletter to find anything of interest.
Remember, your newsletter is not to sell your subscribers anything. At the most, you should only mention a special offer at the bottom with a link to more information. The purpose of your newsletter is to educate your client so they see you as an expert in your field, creating an atmosphere where they come back to you when they need your product or service, and the willingness to refer their friends. Let your website do the selling.