I stumbled across a Twitter profile the other day that had an integrated newsletter sign up option embedded in their profile. Immediately I researched and found Revue and Twitter newsletters.
I spend about 1hr setting up Revue and building a replica of my latest newsletter, soooo much easier to use than MailChimp, at first I added in my Forem RSS feeds to pull in the content but then discovered it was much easier to use the Revue chrome extension to grab all the content I needed then I just dragged it into the newsletter editor.
It's cool, free and allows for custom domains and imports from MailChimp
Check this out: