You can certainly create HTML newsletters template in SeoToaster just like you would with any other page.
You can also create HTML emails, which can then be sent automatically using the ACTION EMAIL & SMS menu or the MERCHANDISING/email remarketing menu when using the ecommerce edition.
You can create a drip & nurture program using the remarketing facility, which will trigger emails based on events such as when someone request a quote, or has abandonned their cart, but you won't be able to do mass-emailing from SEOTOASTER.
It's not that we forgotten to code this functionality, it is just that it is not a good idea to implement it from your CMS.
Instead, we recommend using a commercial service instead such as Constant Contact to perform this action. It will ensure your mass emails get delivered in much greater numbers than if you try to do it from your web server.